Anti-Fog Compositions and Processes for Making Same

ABSTRACT

Anti-fog compositions comprising a primary film having opposing major planar surfaces and a central coplanar region, and processes for making such anti-fog compositions. The central coplanar region is disposed between the opposing major planar surfaces. The primary film comprises cellulose acetate, plasticizer, and an anti-blocking agent. The anti-blocking agent has an average particle size ranging from 0.02 microns to 6 microns. The cellulose acetate has a degree of substitution that increases from the opposing major planar surfaces toward the central coplanar region or that is substantially constant throughout the thickness of the composition. The composition is formed by saponifying a precursor film to improve hydrophilicity.

PRIORITY CLAIM

This application claims priority to U.S. Provisional Application No.61/879,570, filed on Sep. 18, 2013. The entirety of this application isincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to anti-fog compositions andprocesses for making anti-fog compositions. In particular, the presentinvention relates to anti-fog compositions comprising cellulose acetate,plasticizer, and anti-blocking agent.

BACKGROUND OF THE INVENTION

Film compositions are often utilized with many substrates to providebeneficial characteristics and/or properties to the substrate. As oneexample, conventional fog resistant films may be applied to glass ormirrored surfaces to prevent the formation of water droplets thereon.

Many conventional fog resistant films comprise multiple laminatedlayers, e.g., a polycarbonate or polyester layer with a polyurethane orsilane coating. These layers may be formulated so that the layers adhereto one another. In use, however, these layers may separate from oneanother, creating performance and/or durability problems.

Other conventional fog resistant films utilize a one-piececonfiguration. These fog resistant films may comprise a cellulose esterportion and a fog resistant region. The fog resistant film may be formedby treating a cellulose acetate film with an alkali solution. JapanesePatent Application No. 2013099879A and International Publication No.2008/029801A1, both of which are incorporated herein by reference,disclose such fog resistant films and methods for preparing such films.These fog resistant films, however, may suffer from insufficient fogresistance and/or a lack of film transparency, e.g., haziness.

The need exists for an anti-fog composition having improved anti-foggingcharacteristics and/or improved clarity, e.g., reduced haziness.

SUMMARY OF THE INVENTION

In one embodiment, the invention relates to an anti-fog composition,comprising a primary film having opposing major planar surfaces and acentral coplanar region disposed between said opposing major planarsurfaces. The primary film comprises cellulose acetate, plasticizer, andan anti-blocking agent having an average particle size ranging from 0.02microns to 6 microns. The cellulose acetate has a degree of substitutionthat increases from the opposing major planar surfaces toward thecentral coplanar region. The composition may have a degree ofsubstitution at the opposing major planar surfaces of about zero. Thecomposition may have a degree of substitution at the central coplanarregion from 2.0 to 2.6, preferably from 2.2 to 2.55. The composition mayhave a fog time, as defined herein, greater than 10 seconds. Thecomposition may have a haze value ranging from 0.1% to 4.0%, as measuredby ASTM D1003. The plasticizer may be selected from the group consistingof 1,2,3-triacetoxypropane (triacetin), tributyl citrate, triethylcitrate, triphenyl phosphate, tris(clorisopropyl)phosphate, dimethylphthalate, bornan-2-one, PEG-DGE, PPG-DGE, tributyl phosphate, andcombinations thereof. In preferred embodiments, the plasticizercomprises diethyl phthalate. The anti-blocking agent preferablycomprises silica. The primary film may comprise from 60 wt % to 95 wt %cellulose acetate, from 5 to 40 wt. % plasticizer, and from 0.01 to 10wt. % anti-blocking agent. The primary film may further comprise areleasing agent. The anti-blocking agent may have an average particlesize less than 3 microns, preferably less than 1 micron or from 0.02 to1 micron. The anti-fog composition may have a thickness ranging from 25microns to 2000 microns and may be in the form of a rolled sheet. Theanti-fog composition may or may not comprise discrete layers. Thecomposition may further comprise a protective film adhered to one of themajor planar surfaces. The protective film may comprise a protectivematerial selected from polyesters, polyethylene, and polyethyleneterephthalate, and wherein the protective film is adhered to at leastone of the major planar surfaces with an adhesive. The composition mayfurther comprise an adhesive layer disposed on the other of the majorplanar surfaces of the primary film. The composition may furthercomprise a secondary film adhered to the primary film and havingsubstantially the same composition as the primary film. The compositionmay further comprise a secondary film adhered to the primary film andhaving a composition different from the primary film. The secondary filmmay comprise cellulose acetate, wherein the cellulose acetate in thesecondary film has a degree of substitution greater than the degree ofsubstitution of the primary film.

In one embodiment, the invention relates to a consumer product having aplanar surface and the inventive anti-fog composition disposed on theplanar surface. The consumer product may be selected from the groupconsisting of lenses, windows, screens, glass structures, containers,appliances, plastic, optical devices, and visors. The consumer productmay be a refrigerating device. The anti-fog composition may be adheredto said planar surface with an adhesive.

In one embodiment, the invention relates to an anti-fog compositioncomprising a primary film comprising cellulose acetate, plasticizer, andan anti-blocking agent having an average particle size ranging from 0.02microns to 6 microns. The anti-fog composition has a fog time greaterthan 10 seconds. The plasticizer may comprise a phthalate plasticizerand the anti-blocking agent may comprise silica. The anti-fogcomposition may have a haze value ranging from 0.1% to 4.0%, as measuredby ASTM D1003. The composition may comprise from 60 wt % to 95 wt %cellulose acetate, from 5 to 40 wt. % plasticizer; and from 0.01 to 10wt. % anti-blocking agent.

In one embodiment, the invention relates to an anti-fog compositioncomprising a primary film comprising cellulose acetate, a plasticizer,and an anti-blocking agent. The anti-fog composition may have a fog timegreater than 10 seconds. The anti-fog composition may have a haze valueranging from 0.1% to 4.0%, as measured by ASTM D1003. The anti blockingagent may comprise silica having an average particle size ranging from0.02 microns to 6 microns. The composition may comprise from 60 wt % to95 wt % cellulose acetate, from 5 wt % to 40 wt. % plasticizer; and from0.01 wt % to 10 wt % wt. % anti-blocking agent. The plasticizer maycomprise diethyl phthalate.

In one embodiment, the invention relates to an anti-fog compositioncomprising a primary film comprising a mixture of cellulose acetate aphthalate plasticizer, and an anti-blocking agent having an averageparticle size ranging from 0.02 microns to 6 microns. The anti-fogcomposition may have a moisture, e.g., water, vapor transmission rate(MVTR) greater than 100 g/m²/day. The anti-blocking agent may comprisesilica.

In one embodiment, the invention relates to an anti-fog compositioncomprising a primary film comprising a mixture of cellulose acetate,diethyl phthalate, and an anti-blocking agent comprising silica andhaving an average particle diameter ranging from 0.02 microns to 6microns. The anti-fog composition may have a fog time greater than 10seconds.

In one embodiment, the invention relates to a process for producing ananti-fog composition comprising a primary film, the process comprisingthe steps of combining cellulose acetate, a plasticizer, ananti-blocking agent having an average particle size ranging from 0.02microns to 6 microns and solvent to form a dope, casting the dope toform a precursor film, contacting the precursor film with a causticsolution to form a treated film, washing the treated film to form awashed film, and drying the washed film to form the primary film. Theprimary film may have opposing major planar surfaces and a centralcoplanar region disposed between said opposing major planar surfaces.The cellulose acetate may have a degree of substitution that increasesfrom the opposing major planar surfaces toward the central coplanarregion. The process may further comprise the step of treating theprecursor film with acetone prior to the contacting step. The precursorfilm may have a degree of substitution ranging from 2.0 to 2.6. The dopemay comprise cellulose acetate flake. The caustic solution may comprisean aqueous hydroxide solution. The caustic solution may comprise a 5 to20 wt. % potassium hydroxide solution. The contacting may be conductedfor a residence time ranging from 0.5 minutes to 20 minutes. Thecontacting may be conducted at a temperature ranging from 40° C. to 100°C. The washing may be conducted at a temperature ranging from 0° C. to50° C. The drying may be conducted at a temperature ranging from 50° C.to 120° C. The anti-fog composition may have a fog time greater than 10seconds. The anti-fog composition may have a haze value ranging from0.1% to 4.0%, as measured by ASTM D1003.

In one embodiment, the invention relates to a process for producing amulti-layer anti-fog film composition, comprising the steps of providinga first anti-fog film composition comprising a cellulose acetate, aplasticizer, and an anti-blocking agent having an average particlediameter ranging from 0.02 microns to 6 microns; selecting a second filmcomposition based on a first preferred characteristic; and adhering thefirst anti-fog film composition to the second film composition to formthe multi-layer anti-fog film composition having enhancedcharacteristics. The preferred characteristic may be selected such thatthe first anti-fog composition improves the preferred characteristic.

In one embodiment, the invention relates to an anti-fog compositioncomprising a primary film having a thickness, opposing major planarsurfaces and a central coplanar region disposed between the opposingmajor planar surfaces. The primary film comprises cellulose acetate,plasticizer, and an anti-blocking agent having an average particle sizeless than 6 microns. The degree of substitution throughout the thicknessof the primary film is substantially uniform, and optionally is lessthan 2.6, less than 2.0, less than 1.5, less than 1.0 or less than 0.5,and optionally greater than 0.01. In one aspect, the degree ofsubstitution of the cellulose acetate at the central coplanar region isnot be greater than 10% different from the degree of substitution of atleast one of the opposing major planar surfaces.

In one embodiment, the invention relates to a multi-layer anti-fogcomposition, comprising a primary film having opposing major planarsurfaces and a central coplanar region disposed between the opposingmajor planar surfaces and comprising cellulose acetate having a firstdegree of substitution less than 2.6 and a secondary film havingopposing major planar surfaces and a central coplanar region disposedbetween the opposing major planar surfaces. One of the opposing majorsurfaces of the secondary film is adhered to one of the opposing majorplanar surfaces of the primary film. The secondary film comprisescellulose acetate having a second degree of substitution greater thanthe first degree of substitution. The composition may further comprisean additional film adhered to the other of the opposing major planarsurfaces of the secondary film. The additional film has opposing majorplanar surfaces and a central coplanar region disposed between theopposing major planar surfaces. One of the opposing major surfaces maybe adhered to the other of the opposing major planar surfaces of thesecondary film. The additional film comprises cellulose acetate may havea degree of substitution greater than the second degree of substitution.

In one embodiment, the invention relates to an anti-fog compositioncomprising a primary film having opposing major planar surfaces and acentral coplanar region disposed between said opposing major planarsurfaces. The primary film comprises cellulose acetate, plasticizer,optionally anti-blocking agent, and from 0.01 wt % to 3 wt % acetone.

In one embodiment, the invention relates to an anti-fog compositioncomprising a primary film having opposing major planar surfaces and acentral coplanar region disposed between said opposing major planarsurfaces. The primary film comprises cellulose acetate, plasticizer, andan anti-blocking agent having an average particle size ranging from 0.02microns to 6 microns.

In one embodiment, the invention relates to a multi-layer anti-fogcomposition, comprising a first primary film having opposing majorplanar surfaces and a central coplanar region disposed between theopposing major planar surfaces and comprising cellulose acetateplasticizer, and an anti-blocking agent having an average particle sizeranging from 0.02 microns to 6 microns with the cellulose acetate havinga degree of substitution that increases from the opposing major planarsurfaces toward the central coplanar region; a secondary film havingopposing major planar surfaces and a central coplanar region disposedbetween the opposing major planar surfaces with one of the opposingmajor surfaces of the secondary film being adhered to one of theopposing major planar surfaces of the first primary film; and a secondprimary film having opposing major planar surfaces and a centralcoplanar region disposed between the opposing major planar surfaces andcomprising cellulose acetate plasticizer, and an anti-blocking agenthaving an average particle size ranging from 0.02 microns to 6 micronswith the cellulose acetate having a degree of substitution thatincreases from the opposing major planar surfaces toward the centralcoplanar region. The other of the opposing major surfaces of thesecondary film is adhered to one of the opposing major planar surfacesof the second primary film.

In one embodiment, the invention relates to a process for producing ananti-fog composition comprising a primary film comprising the steps ofextruding pellets comprising cellulose acetate, a plasticizer, and ananti-blocking agent having an average particle size ranging from 0.02microns to 6 microns, and optionally an antioxidant and/or a heatstabilizer, to form a precursor film, preferably having a thickness lessthan 300 microns, more preferably less than 200 microns; contacting theprecursor film with a caustic solution to form a treated film; washingthe treated film to form a washed film; and drying the washed film toform the primary film.

DETAILED DESCRIPTION OF THE INVENTION

It has now been discovered that the caustic treatment of a filmprecursor formed using a specific anti-blocking agent having aparticularly small average particle size, e.g., from 0.02 microns to 6microns, results in the preparation of a fog resistant (anti-fog)composition having a superior combination of properties, e.g., increasedfog time and reduced haziness. The compositions of the inventionbeneficially do not exhibit the separation problems that are commonlyobserved with conventional fog resistant films.

Anti-Fog Composition and Primary Film

In the production processes, a precursor film is prepared, preferably bysolvent casting a dope comprising cellulose acetate, a plasticizer, ananti-blocking agent and solvent. The precursor film is treated with acaustic solution, e.g., a basic solution such as a potassium hydroxidesolution, under conditions effective to form an anti-fog compositionthat, in use, allows some moisture to seep into or absorb into theanti-fog composition (as opposed to allowing the water to pool atop thefilm).

Without being bound by theory, the specific caustic treatment of theprecursor film modifies, e.g., reduces, the degree of acetylsubstitution of the cellulose acetate increasing its anti-fogcharacteristics. When the specific caustic treatment is utilized totreat a precursor formed from the particular components discussedherein, a unique anti-fog composition having a highly desirablecombination of performance characteristics is formed. Depending on thecaustic treatment conditions, e.g., thickness of the precursor filmand/or caustic treating time, the degree of substitution of theresulting anti-fog film may be substantially constant throughout thefilm or may increase from opposing major planar surfaces of the filmtoward a center coplanar region of the film. Modifying, e.g., reducing,the degree of substitution of the precursor film in this manner providesfor increased hydrophilicity near the major planar surfaces of theanti-fog composition, allowing for increased water absorption andimproved anti-fogging characteristics.

The present invention also relates to the anti-fog compositions formedby the processes of the invention. In one embodiment, the anti-fogcomposition comprises a primary film having opposing major planarsurfaces and a central coplanar region. The central coplanar region isdisposed between the opposing major planar surfaces. In one embodiment,the primary film comprises cellulose acetate, plasticizer, and ananti-blocking agent. The anti-blocking agent may have an averageparticle size less than 6 microns, e.g., less than 5 microns, less than4 microns, less than 3 microns, less than 2 microns, or less than 1micron. In terms of ranges, the anti-blocking agent desirably has asmall average particle size, e.g., from 0.02 microns to 6 microns, from0.02 microns to 5 microns, from 0.02 microns to 3 microns, from 0.02microns to 1 micron, from 0.05 microns to 6 microns, from 0.05 micronsto 5 microns, from 0.1 micron to 5 microns, from 0.1 microns to 4microns, from 0.5 microns to 5 microns, from 0.5 microns to 4 microns,from 0.5 microns to 3 microns, from 0.5 microns to 3 microns, from 1micron to 6 microns, from 1 micron to 5 microns, or from 1 micron to 4microns. The particle size may be determined, for example, by sieveanalysis. Many conventional anti-fog compositions, e.g., those formedvia extrusion processes, do not experience inter-layer problems, e.g.,“glass bonding effects,” which necessitate the use of anti-blockingagents. Thus, conventional extrusion-formed films typically do notcontain anti-blocking agents.

In some embodiments, the cellulose acetate in the primary film has adegree of substitution that increases from the opposing major planarsurfaces toward the central coplanar region. That is, the anti-fogcomposition may have a “decreasing degree of substitution gradient,”e.g., a degree of substitution that is less at the outside planarsurfaces of the anti-fog composition and increases toward the centercoplanar region of the anti-fog composition. In one embodiment, thedegree of substitution at one or more of the opposing major planarsurfaces is less than 2.6, e.g., less than 2.55, less than 2.5, lessthan 2.0, less than 1.5, less than 1.0, or less than 0.5. In terms oflower limits, the degree of substitution at one or more of the opposingmajor planar surfaces may be at least 0.1, e.g., at least 0.2, at least0.3, or at least 0.5. In one embodiment, the degree of substitution atone or more of the opposing major planar surfaces is substantially zero,e.g., from 0 to 0.5 or from 0 to 0.25. In terms of ranges, the degree ofsubstitution at one or more of the opposing major planar surfaces mayrange from 0 to 2.6, e.g., from 0 to 2.55, from 0.1 to 2.5, from 0.2 to2, or from 0.3 to 1.5. In some embodiments, the degree of substitutionat the central coplanar region ranges from 2.0 to 2.6, e.g., from 2.0 to2.55, from 2.1 to 2.55, from 2.2 to 2.55, or from 2.3 to 2.55. In termsof upper limits, the degree of substitution at the central coplanarregion may be less than 2.6, e.g., less than 2.55, less than 2.5, lessthan 2.4, less than 2.3, or less than 2.2, but preferably at least 2.0,e.g., at least 2.1, or at least 2.3. The degree of substitution of theprimary film affects the hydrophilicity of the precursor film and itsability to act as an anti-fog composition, with lower degrees ofsubstitution corresponding to increased hydrophilicity. The increasedhydrophilicity in turn allows for increased water absorption in theprimary film, which beneficially provides for a longer lastinganti-fogging effect. The combination of this longer lasting anti-foggingeffect with the improvements in haze properties (as provided for byutilizing the specific composition of the precursor film) results in ahighly desirable anti-fog composition.

In some embodiments, the anti-fog composition comprises a primary filmhaving opposing major planar surfaces and a central coplanar region thatis disposed between the opposing major planar surfaces, and thecellulose acetate in the primary film of the anti-fog compositions has adegree of substitution that is substantially uniform over the (crosssectional) thickness of the anti-fog composition, optionally varying byno more than 0.75, by no more than 0.5, or by no more than 0.25,throughout the thickness of the primary film. In some embodiments, thecellulose acetate in the primary film of the anti-fog composition has adegree of substitution less than 2.6, e.g., less than 2.55, less than2.5, less than 2.45, less than 2.3, less than 2.0, less than 1.75, lessthan 1.5, less than 1.0, less than 0.75, or less than 0.5. In terms ofranges, the degree of substitution of the cellulose acetate may rangefrom 0 to 2.6, e.g., from 0 to 2.55, from 0 to 2.5, from 0.1 to 2.55, orfrom 0.1 to 1, between the opposing major planar surfaces. In oneembodiment, the degree of substitution of the cellulose acetate at thecentral coplanar region is not greater than 10% different, e.g., notgreater than 5% different, from the degree of substitution of at leastone of the opposing major planar surfaces. Such anti-fog compositionswill have a low and substantially uniform degree of substitution, ascompared to conventional films, e.g., films than have not beensufficiently treated. Also, such anti-fog compositions comprise thecomponents discussed herein, which are not present in conventionalanti-fog compositions formed by other production methods, e.g.,extrusion methods. In one embodiment, the anti-fog composition may beproduced by forming a precursor film, e.g., using the componentsdiscussed herein, and then treating the precursor film with a causticsolution. The precursor film may be treated with the caustic solutiontreatment for an extended period of time, as compared to conventionaltreatments, which may only last a few seconds. For example, the causticsolution treatment may be performed for at least 5 minutes, e.g., atleast 7 minutes, at least 10 minutes, at least 12 minutes, at least 15minutes, at least 17 minutes, or at least 20 minutes. Such anti-fogcompositions have the beneficial characteristics of improvedanti-fogging characteristics and/or improved clarity, e.g., lack ofhaziness, as a result of the combination of the caustic treatment stepand the specific precursor film composition.

The thickness of the precursor film may be a factor in the duration ofthe caustic solution treatment and the resulting characteristics of theanti-fog compositions. For example, a thinner film may require a shortertreatment time to achieve the desired anti-fog property than a thickerfilm.

The primary film, in some embodiments, does not comprise discretelayers, unlike some conventional films that utilize a multi-layerconstruction comprising a base layer, e.g., a cellulose acetate layer, apolycarbonate layer, or a polyethylene teraphthalate layer, and ananti-fog layer. As such, the present anti-fog compositions beneficiallymay avoid the problems associated with adherence of an anti-fog layer toa base layer, e.g., eventual separation of the layers during use.

The anti-fog composition, in one embodiment, comprises from 60 wt % to95 wt % cellulose acetate, e.g., from 65 wt % to 90 wt %, from 70 wt %to 90 wt %, or from 75 wt % to 85 wt %. In terms of lower limits, theanti-fog composition may comprise at least 60 wt % cellulose acetate,e.g., at least 65 wt %, at least 70 wt % or at least 75 wt %. In termsof upper limits, the anti-fog composition may comprise less than 95 wt %cellulose acetate, e.g., less than 90 wt % or less than 85 wt %.

The anti-fog composition, in one embodiment, comprises from 5 wt % to 40wt % plasticizer, e.g., from 5 wt % to 35 wt %, from 10 wt % to 30 wt %,or from 15 wt % to 25 wt %. In terms of lower limits, the anti-fogcomposition may comprise at least 60 wt % plasticizer, e.g., at least 5wt %, at least 10 wt % or at least 15 wt %. In terms of upper limits,the anti-fog composition may comprise less than 95 wt % plasticizer,e.g., less than 40 wt %, less than 35 wt %, less than 30 wt %, or lessthan 25 wt %.

The anti-fog composition, in one embodiment, comprises from 0.01 wt % to10 wt % anti-blocking agent, e.g., from 0.05 wt % to 5 wt %, from 0.05wt % to 1 wt %, or from 0.05 wt % to 0.5 wt %. In terms of lower limits,the anti-fog composition may comprise at least 0.01 wt %, at least 0.05wt % or at least 0.07 wt % anti-blocking agent. In terms of upperlimits, the anti-fog composition may comprise less than 10 wt %anti-blocking agent, e.g., less than 7 wt %, less than 5 wt %, less than1 wt %, or less than 0.5 wt %. Additional details of the components ofthe above-mentioned components are provided herein.

In some embodiments, particular anti-fog compositions have uniquecombinations of components, which result in desired performancecharacteristics. For example, the plasticizer may comprise a phthalateplasticizer such as diethyl phthalate. The anti-blocking agent maycomprise silica. In some cases, combinations of these specificcomponents result in anti-fog compositions having the desirablecharacteristics discussed herein. As another example, the primary filmcomprises cellulose acetate, plasticizer (e.g., phthalate plasticizersuch as diethyl phthalate plasticizer, optionally anti-blocking agent(e.g., silica) and from 0.01 wt % to 3 wt % acetone.

In some embodiments, the anti-fog composition further comprises areleasing agent, which allows the anti-fog composition to release fromvarious components during or after the production process, e.g.,releasing from a casting band. In one embodiment, the anti-fogcomposition comprises from 0.01 wt % to 10 wt % releasing agent, e.g.,from 0.05 wt % to 5 wt %, from 0.05 wt % to 1 wt %, or from 0.05 wt % to0.5 wt %. In terms of lower limits, the anti-fog composition maycomprise at least 0.01 wt %, at least 0.05 wt % or at least 0.07 wt %releasing agent. In terms of upper limits, the anti-fog composition maycomprise less than 10 wt % releasing agent, e.g., less than 7 wt %, lessthan 5 wt %, less than 1 wt %, or less than 0.5 wt %. The composition ofthe releasing agent may vary widely, and many releasing agents are knownin the art. In one embodiment, the releasing agent comprises stearicacid. The releasing agent is preferably added to, e.g., mixed into, thedope. In such cases, the release agent preferably is dissolved into thedope. In one embodiment, the releasing agent is deposited or injectedonto the casting band upon which the anti-fog composition is cast. Asthe anti-fog composition is released from the casting band, some of thereleasing agent may remain with the anti-fog composition and/or some ofthe release agent may remain with the casting band (based on theattraction of the release agent to the metal).

In some embodiments, the anti-fog composition comprises residual acetonefrom the manufacturing process. For example, the anti-fog compositionmay comprise from 0.01 wt % to 3 wt % acetone, e.g., from 0.05 wt % to 2wt %, from 0.05 wt % to 1 wt %, or from 0.05 to 0.5 wt %. In terms oflower limits, the anti-fog composition may comprise at least 0.01 wt %acetone, e.g., at least 0.05 wt % or at least 0.1 wt %. In terms ofupper limits, the anti-fog composition may comprise less than 3 wt %acetone, e.g., less than 2 wt %, less than 1 wt %, less than 0.5 wt %,or less than 0.1 wt %.

Performance Characteristics

The anti-fog composition, in some embodiments, has a fog time greaterthan 20 seconds, e.g., greater than 30 seconds, greater than 40 seconds,greater than 50 seconds, greater than 60 seconds, or greater than 70seconds. In terms of ranges, the anti-fog composition may have a fogtime ranging from 20 seconds to 150, e.g., from 20 seconds to 100seconds or from 30 seconds to 90 seconds. In one embodiment, the fogtime may be determined by placing an anti-fog film of the invention overa beaker of heated water, e.g., heated to approximately 50° C., andmeasuring the time taken for a fog to form, if any. The sample may beplaced at a predetermined distance from the film, e.g., approximately 6cm. In other cases, test methods EN166 and/or EN168.16 may be utilized.

The anti-fog composition, in some embodiments, has a haze value, e.g.,an ASTM D1003 haze value, less than 2%, e.g., less than 1.5%, less than1.2%, or less than 1%. In terms of ranges, the anti-fog composition mayhave a haze value ranging from 0 to 2%, e.g., from 0.1% to 1.5%, from0.2% to 1%, or from 0.6% to 1%. In one embodiment, the haze may bemeasured by hazemeter. In one embodiment, haze may be measured withproperly sized specimens having substantially plane-parallel surfaces,e.g., flat without wrinkling, free of dust, scratches, and particles, ofabout 0.85 mm in thickness using an UtraScan Pro analyzer from HunterLabs with haze setting of D65/10.

In one embodiment, the anti-fog composition has haze Δ ranging from 0%to 10% as determined measuring haze before and after rubbing with amicrofiber cloth under 1 pound of weight, e.g., from 0% to 5%, from 0%to 1%, or from 0% to 0.1%. In terms of lower limits, the anti-fogcomposition may have a haze Δ less than 10%, e.g., less than 5%, lessthan 1% or less than 0.1%.

In one embodiment, the anti-fog composition has a moisture (water) vaportransmission rate (MVTR) ranging from 100 g/m²/day to 1000 g/m²/day (at25° C. and 75% relative humidity), e.g., from 200 g/m²/day to 1000g/m²/day or from 250 g/m²/day to 750 g/m²/day. In terms of lower limits,the anti-fog composition may have a water vapor transmission rategreater than 100 g/m²/day, e.g., greater than 200 g/m²/day, or greaterthan 250 g/m²/day. In terms of upper limits, the anti-fog compositionmay have a water vapor transmission rate less than 1000 g/m²/day, e.g.,less than 900 g/m²/day, or less than 750 g/m²/day. Water vaportransmission rate may be measured by gravimetric techniques. In oneembodiment, the water vapor transmission rate is measured as noted inone of the following ASTM test standards: ASTM F1249-06, ASTM E398-03,ASTM D1434, ASTM D3079, ASTM D4279, ASTM E96, ASTM E398, ASTM F1249,ASTM F2298, or ASTM F2622.

In one embodiment, the anti-fog composition has a transparency rangingfrom 40% to 100%, as measured by ASTM D1746, e.g., from 70% to 90%. Interms of lower limits, the anti-fog composition may have a transparencygreater than 40%, e.g., greater than 70%. In terms of upper limits, theanti-fog composition may have a transparency less than 100%, e.g., lessthan 90%.

In one embodiment, the anti-fog composition has a light diffusionranging from 0.1 cd/m²/lx to 0.26 cd/m²/lx as measured by EN 167 4,e.g., from 0.15 cd/m²/lx to 0.25 cd/m²/lx. In terms of lower limits, theanti-fog composition may have a light diffusion greater than 0.1cd/m²/lx, e.g., greater than 0.15 cd/m²/lx. In terms of lower limits,the anti-fog composition may have a light diffusion less than 0.26cd/m²/lx e.g., less than 0.25 cd/m²/lx.

In one embodiment, the anti-fog composition has a gloss ranging from 100to 200 as measured by ASTM D5423, e.g., from 125 to 175, or from 145 to155. In terms of lower limits, the anti-fog composition may have a lightdiffusion greater than 100, e.g., greater than 125 or greater than 145.In terms of upper limits, the anti-fog composition may have a lightdiffusion less than 200 e.g., less than 175 or less than 155.

In one embodiment, the anti-fog composition has a tensile strengthranging from 40 Nmm⁻² to 140 Nmm⁻², as measured by ASTM D882, e.g., from70 Nmm⁻² to 110 Nmm⁻². In terms of lower limits, the anti-fogcomposition may have a tensile strength greater than 40 Nmm⁻², e.g.,greater than 70 Nmm⁻². In terms of upper limits, the anti-fogcomposition may have a tensile strength less than 140 Nmm⁻², e.g., lessthan 90 Nmm⁻².

In one embodiment, the anti-fog composition has an elongation rangingfrom 20% to 60%, as measured by ASTM D882, e.g., from 25%² to 55%. Interms of lower limits, the anti-fog composition may have an elongationgreater than 20%, e.g., greater than 25%. In terms of upper limits, theanti-fog composition may have an elongation less than 60%, e.g., lessthan 55%.

In one embodiment, the anti-fog composition has a Young's modulusranging from 1400 Nmm⁻² to 2400 Nmm⁻², as measured by ASTM D882, e.g.,from 1600 Nmm⁻² to 2200 Nmm⁻², or from 1800 Nmm⁻² to 2000 Nmm⁻². Interms of lower limits, the anti-fog composition may have a Young'smodulus greater than 1400 Nmm⁻², e.g., greater than 1600 Nmm⁻², orgreater than 1800 Nmm⁻². In terms of upper limits, the anti-fogcomposition may have a Young's modulus less than 2400 Nmm⁻², e.g., lessthan 2200 Nmm⁻² or less than 2000 Nmm⁻².

The dimensions of the primary film may vary widely. In one embodiment,the primary film has a thickness ranging from 25 microns to 2000microns, e.g., from 25 microns to 1000 microns, from 25 microns to 750microns, from 50 microns to 500 microns, or from 75 microns to 200microns. In terms of lower limits, the thickness of the primary film maybe greater than 25 microns, e.g., greater than 50 microns or greaterthan 75 microns. In terms of upper limits, the thickness of the primaryfilm may be less than 2000 microns, e.g., less than 1000 microns, lessthan 750 microns, less than 500 microns, or less than 200 microns.Thicknesses may be measured via the methods known in the art, e.g.,infrared scanning.

Multi-Layer Configurations

The configuration and/or dimensions of the anti-fog compositions alsomay vary widely. In some cases, the anti-fog composition may compriseone layer, i.e., the above-described primary film. In other embodiments,the anti-fog composition may comprise multiple layers, e.g., 2 or morelayers, 3 or more layers, 4 or more layers or 5 or more layers. In thisaspect, the thickness of the anti-fog composition (including all layers)may range from 200 microns to 2000 microns, e.g., from 200 microns to1000 microns, from 250 microns to 750 microns, or from 275 microns to500 microns. In terms of lower limits, the thickness of the anti-fogcomposition may be greater than 200 microns, e.g., greater than 250microns or greater than 275 microns. In terms of upper limits, thethickness of the anti-fog composition may be less than 2000 microns,e.g., less than 1000 microns, less than 750 microns, less than 500microns, or less than 200 microns. In embodiments in which multiplelayers are employed, the layers may be adhered to one another, e.g.,laminated or attached to one another, optionally with an adhesive. Theterm “adhered” broadly encompasses any method used to connect multiplelayers and may or may not involve the use of a separate adhesive. In oneembodiment, adhering may be achieved by contacting the layers withacetone and stacking the contacted layers, preferably before caustictreatment, to form a bond between the layers. In other embodiments,especially where greater thickness is preferred, an adhesive may beemployed to adhere the layers to one another. Various adhesives areknown in the art. In one embodiment, the primary film (and the anti-fogcomposition as a whole) may be in the form of a rolled sheet.

In one embodiment, the anti-fog composition further comprises aprotective film. The protective film may be adhered to at least one ofthe major planar surfaces. In some cases, the protective film may beadhered to only one major planar surface. The protective film may be afairly low tack film that protects the anti-fog composition, e.g., thesurface thereof, from damage, e.g., physical, light-related, or chemicaldamage. In use, the protective film may be peeled away from the anti-fogcomposition, optionally after application to a suitable substrate. Thespecific composition of the protective film may vary widely. In someembodiments, the protective film comprises a protective materialselected from polyesters, polyethylenes, and polyethylene terephthalate.The protective film may be adhered to at least one of the major planarsurfaces with a suitable adhesive, e.g., an acrylic polymer.

In some cases, the anti-fog composition comprises an adhesive layerattached to one major planar surface. In one embodiment, the anti-fogcomposition comprises an adhesive layer adhered to one major planarsurface and a protective layer attached, e.g., adhered, to the othermajor planar surface. The adhesive layer may then have a release filmattached thereto. The anti-fog composition may be in the form of a flatsheet or rolled sheet.

In some configurations, the anti-fog composition comprises the primaryfilm and a secondary film. The secondary film may be adhered to theprimary film. In one embodiment, the secondary film has substantiallythe same composition as the primary film. This configuration may beuseful when a greater thickness and a uniform composition are desired.In one embodiment, multiple precursor layers may be formed and thenstacked upon one another, e.g., to achieve a thicker precursor film. Thestacked precursor film may then be treated with caustic solution.

In one embodiment, the secondary film has a composition different fromthe primary film. This configuration may be useful when a largerthickness is desired, but a uniform composition is not necessary, e.g.,when only the surface of the film requires anti-fog characteristics, andthe central or middle region does not require anti-fog characteristics.For example, the secondary film may comprise cellulose acetate, and thecellulose acetate in the secondary film may have a degree ofsubstitution greater than that of the primary film, e.g., outer majorplanar surface of the primary film, which preferably has a degree ofsubstitution as discussed herein. For example, the secondary film maynot be saponified and the primary film may be saponified. Such aconfiguration may provide cost advantages and allow for the building upof thick films or sheets having the desired anti-fog characteristics onthe exterior major planar surface of the anti-fog composition. In oneembodiment, the anti-fog composition employs the primary film (withanti-fog characteristics) on one side of the composition and a secondarylayer that does not have anti-fog characteristics. Such a configurationmay be useful in cases where the end substrate is used in coldertemperatures, e.g., ski/skydiving goggles, airplane windows.

In some embodiments, one or more films are utilized in conjunction withthe primary film. Suitable adhesives, e.g., ethylene-vinyl acetateadhesives, may be utilized to attach the primary film to the additionalfilm(s). Many film layers can be utilized, e.g., more than 3, more than4, or more than 5. In some embodiments, as noted above, acetone can becontacted with the primary film and/or to one or more additional filmsto adhere the layers to one another. This addition of acetone andadhering of the films may be implemented before saponification of theprecursor film. In cases where the layers have been saponified, it maybe beneficial to utilize an adhesive to adhere the layers to oneanother.

In one embodiment, the invention relates to a multi-layer anti-fogcomposition. The multi-layer anti-fog composition comprises a primaryfilm as discussed herein. The primary film comprises cellulose acetatehaving a first degree of substitution. The first degree of substitutionmay be less than 2.55, e.g., less than 2.5, less than 2.0, or less than1.5. Other ranges discussed herein also apply to multi-layerconfigurations. The multi-layer anti-fog composition also comprises asecondary film. One of the major planar surfaces of the secondary filmis adhered, optionally with an adhesive, to one of the major planarsurfaces of the primary film. The composition of the secondary film mayvary widely. In some embodiments, the secondary film may be a polymerfilm, e.g., a polycarbonate film or a polyester film. In one embodiment,the secondary film may comprise cellulose acetate, optionallynon-saponified cellulose acetate. In some of these cases, the secondaryfilm comprising cellulose acetate has a second degree of substitutiongreater than the first degree of substitution. In one embodiment, themulti-layer anti-fog composition further comprises an additionalanti-fog film adhered to the other of the opposing major planar surfacesof the secondary film. In this case, the multi-layer anti-fogcomposition would comprise a standard, preferably non-saponified, filmsandwiched between two saponified films, e.g., the additional film hasopposing major planar surfaces and a central coplanar region disposedbetween the opposing major planar surfaces and one of the opposing majorsurfaces is adhered to the other of the opposing major planar surfacesof the secondary film. In one aspect of this embodiment, the additionalfilm comprises cellulose acetate having a degree of substitution lessthan that of the secondary film. The secondary film is not limited tocellulose acetate films. For example, the secondary film may be anon-saponified polycarbonate or polyester film. In this case, themulti-layer anti-fog composition would comprise a standard polymer film,e.g., a polycarbonate or polyester film, sandwiched by two saponified(cellulose acetate-containing) films. In some embodiments, multiplenon-saponified secondary films, of same or different composition, may beadhered together, with or without adhesive, and the resultingmulti-layer structure may be sandwiched between the above-describedprimary film and the above-described additional film.

Main Precursor Film Components

Cellulose is generally known to be a semi-synthetic polymer containinganhydroglucose repeating units with three hydroxyl groups peranhydroglucose unit. Cellulose acetate may be formed by esterifyingcellulose after activating the cellulose with acetic acid. The cellulosemay be obtained from numerous types of cellulosic material, includingbut not limited to plant derived biomass, corn stover, sugar cane stalk,bagasse and cane residues, rice and wheat straw, agricultural grasses,hardwood, hardwood pulp, softwood, softwood pulp, cotton linters,switchgrass, bagasse, herbs, recycled paper, waste paper, wood chips,pulp and paper wastes, waste wood, thinned wood, willow, poplar,perennial grasses (e.g., grasses of the Miscanthus family), bacterialcellulose, seed hulls (e.g., soy beans), cornstalk, chaff, and otherforms of wood, bamboo, soyhull, bast fibers, such as kenaf, hemp, juteand flax, agricultural residual products, agricultural wastes,excretions of livestock, microbial, algal cellulose, seaweed and allother materials proximately or ultimately derived from plants. Suchcellulosic raw materials are preferably processed in pellet, chip, clip,sheet, attritioned fiber, powder form, or other form rendering themsuitable for further purification. Combinations of sources are alsowithin the contemplation of the invention.

Cellulose esters suitable for use in producing the anti-fog compositionof the present invention may, in some embodiments, have estersubstituents that include, but are not limited to, C₁-C₂₀ aliphaticesters (e.g., acetate, propionate, or butyrate), functional C₁-C₂₀aliphatic esters (e.g., succinate, glutarate, maleate) aromatic esters(e.g., benzoate or phthalate), substituted aromatic esters, and thelike, any derivative thereof, and any combination thereof. Celluloseesters suitable for use in producing the anti-fog composition of thepresent invention may, in some embodiments, have a molecular weightranging from a lower limit of about 10,000, 15,000, 25,000, 50,000, or85,000 to an upper limit of about 125,000, 100,000, or 85,000, andwherein the molecular weight may range from any lower limit to any upperlimit and encompass any subset therebetween. In one embodiment, thenumber average molecular weight of the cellulose acetate may range from40,000 amu to 100,000 amu, e.g., from 50,000 amu to 80,000 amu.

The cellulose acetate used in the production of the anti-fog compositionmay be cellulose diacetate or cellulose triacetate. In one embodiment,the cellulose acetate comprises cellulose diacetate. Cellulose acetatehas an acetyl value, which is a measure of the degree of substitution ofthe cellulose acetate. The acetyl value represents the weight percent ofacetic acid liberated by the saponification of cellulose acetate. Theacetyl value and degree of substitution are linearly related. The degreeof substitution may be calculated from the acetyl value according to thefollowing formula:

${{Degree}\mspace{14mu} {of}\mspace{14mu} {substitution}} = \frac{{Acetyl}\mspace{14mu} {value} \times 162}{6005 - \left( {{Acetyl}\mspace{14mu} {value} \times 42} \right)}$

In the production of the anti-fog composition various solvents andadhesives may be used as bonding agents to bond continuous film layerstogether and to bond opposing cellulose acetate layers together. Thesolubility and, hence, bonding ability of cellulose acetate in a solventdepends, at least in part, on the acetyl value of the cellulose acetate.As the acetyl value decreases, solubility of the cellulose acetate mayimprove in ketones, esters, nitrogen-containing compounds, glycols andethers. As the acetyl value increases, solubility of the celluloseacetate may improve in halogenated hydrocarbons. As a result, the acetylvalue and degree of substitution of the cellulose acetate employed aswell as the desired bonding agent for bonding the continuous film layersmay impact the ability to form durable and mechanically uniform anti-fogcompositions.

The cellulose acetate may be utilized in powder or flake form,preferably flake form, to form the dope used in a solvent castingprocess to form the precursor film. In other embodiments, the celluloseacetate, in powder or flake form, may be formulated and injection moldedinto pellets that may be extruded into the precursor film.

The flake form of cellulose acetate may have an average flake size from5 μm to 10 mm, as determined by sieve analysis. The flake preferably haslow moisture content, optionally comprising less than 6 wt % water,e.g., less than 5 wt % water or less than 2.5 wt % water. In terms ofranges, the flake form may have from 0.01 to 6 wt % water, e.g., from0.1 to 2.5 wt % water or from 0.5 to 2.45 wt % water. Prior to mixing,the cellulose acetate flake may be heated to remove moisture. In someembodiments, the cellulose acetate flake may be dried until it has awater content of less than 2 wt. %, e.g., less than 1.5 wt. %, less than1 wt. % or less than 0.2 wt. %, The drying may be conducted at atemperature from 30 to 100° C., e.g., from 50 to 80° C. and for a periodof 1 to 24 hours, e.g., from 5 to 20 hours or from 10 to 15 hours.

The plasticizer may vary widely. Suitable plasticizers may, in someembodiments, include, but are not limited to, triacetin, trimethylphosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate,triethyl citrate, acetyl trimethyl citrate, acetyl triethyl citrate,acetyl tributyl citrate, dibutyl phthalate, diaryl phthalate, diethylphthalate, dimethyl phthalate, di-2-methoxyethyl phthalate, di-octylphthalate (and isomers), dibutyl tartrate, ethyl o-benzoylbenzoate,ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate,n-ethyltoluenesulfonamide, o-cresyl p-toluenesulfonate, aromatic diol,substituted aromatic diols, aromatic ethers, tripropionin,polycaprolactone, glycerin, glycerin esters, diacetin, polyethyleneglycol, polyethylene glycol esters, polyethylene glycol diesters,di-2-ethylhexyl polyethylene glycol ester, diethylene glycol,polypropylene glycol, polyglycoldiglycidyl ethers, dimethyl sulfoxide,N-methyl pyrollidinone, propylene carbonate, C₁-C₂₀ diacid esters,dimethyl adipate (and other dialkyl esters), resorcinol monoacetate,catechol, catechol esters, phenols, epoxidized soy bean oil, castor oil,linseed oil, epoxidized linseed oil, other vegetable oils, other seedoils, difunctional glycidyl ether based on polyethylene glycol,alkylphosphate esters, phospholipids, aromas (including some describedherein, e.g., eugenol, cinnamyl alcohol, camphor, methoxy hydroxyacetophenone (acetovanillone), vanillin, and ethylvanillin), and thelike, any derivative thereof, and any combination thereof. In someembodiments, plasticizers may be food-grade plasticizers. Examples offood-grade plasticizers may, in some embodiments, include, but are notlimited to, triacetin, trimethyl citrate, triethyl citrate, tributylcitrate, eugenol, cinnamyl alcohol, methoxy hydroxy acetophenone(acetovanillone), vanillin, ethylvanillin, polyethylene glycols, and thelike, and any combination thereof.

In one embodiment, the plasticizer is selected from the group consistingof 1,2,3-triacetoxypropane (triacetin), tributyl citrate, diethylphthalate, triethyl citrate, triphenyl phosphate,tris(clorisopropyl)phosphate, dimethyl phthalate, bornan-2-one, PEG-DGE,PPG-DGE, tributyl phosphate, and combinations thereof. In one embodimentthe plasticizer comprises a phthalate plasticizer. In preferredembodiments, the plasticizer comprises diethyl phthalate. In someembodiments, the anti-fog composition comprises, inter alia, diethylphthalate and silica having an average particle size ranging from 0.02microns to 6 microns. In one embodiment, the plasticizer does notcomprise triacetin.

The anti-blocking agent may vary widely, as long as the physical sizerange is maintained. In preferred embodiments, the anti-blocking agentcomprises an inorganic compound. For example, the anti-blocking agentmay comprise oxides, carbonates, talc, clay, kaolin, silicates, and/orphosphates. In one embodiment, the anti-blocking agent may be selectedfrom the group consisting of titanium dioxide, aluminum oxide, zirconiumoxide, silicon dioxide, calcium carbonate, calcium silicate, aluminumsilicate, magnesium silicate, calcium phosphate and mixtures thereof. Inone embodiment, the anti-blocking agent comprises silica. Some suitablecommercial products include Aerosil® products (from Evonik IndustriesAG, Germany). One specific suitable commercial product is Aerosil R972.

Optional Additives

In some embodiments, the anti-fog composition, and the dope preferablyused to form the anti-fog composition, may further comprise one or moreadditional additives, e.g., tackifiers, flame retardants, antioxidants,antibacterial agents, antifungal agents, colorants, pigments, dyes,UV-stabilizers, viscosity modifiers, processing additives, aromas, andthe like, and any combination thereof. The amount of the additives mayvary widely. Generally speaking the one or more additives may be presentin an amount ranging from 0.01 to 10 wt. %, based on the total weight ofthe anti-fog composition, e.g., from 0.03 to 2 wt. %, or from 0.1 to 1wt. %.

In one embodiment, UV absorber additives may be included in the anti-fogcomposition. For example, the anti-fog composition (with a UV absorberadditive) may be utilized in a situation where UV light may damage thecontents enclosed by the anti-fog composition. One example may include arefrigerator or freezer in which the anti-fog composition (with a UVabsorber additive) is utilized to protect meat or fish from potentiallydamaging UV light.

Tackifiers may, in some embodiments, increase the adhesive properties ofthe anti-fog composition described herein. Tackifiers suitable for usein conjunction with the anti-fog composition described herein may, insome embodiments, include, but are not limited to, methylcellulose,ethylcellulose, hydroxyethylcellulose, carboxy methylcellulose, carboxyethylcellulose, amides, diamines, polyesters, polycarbonates,silyl-modified polyamide compounds, polycarbamates, urethanes, naturalresins, natural rosins, shellacs, acrylic acid polymers,2-ethylhexylacrylate, acrylic acid ester polymers, acrylic acidderivative polymers, acrylic acid homopolymers, anacrylic acid esterhomopolymers, poly(methyl acrylate), poly(butyl acrylate),poly(2-ethylhexyl acrylate), acrylic acid ester co-polymers, methacrylicacid derivative polymers, methacrylic acid homopolymers, methacrylicacid ester homopolymers, poly(methyl methacrylate), poly(butylmethacrylate), poly(2-ethylhexyl methacrylate),acrylamido-methyl-propane sulfonate polymers, acrylamido-methyl-propanesulfonate derivative polymers, acrylamido-methyl-propane sulfonateco-polymers, acrylic acid/acrylamido-methyl-propane sulfonateco-polymers, benzyl coco di-(hydroxyethyl) quaternary amines,p-T-amyl-phenols condensed with formaldehyde, dialkyl aminoalkyl(meth)acrylates, acrylamides, N-(dialkyl amino alkyl) acrylamide,methacrylamides, hydroxy alkyl(meth)acrylates, methacrylic acids,acrylic acids, hydroxyethyl acrylates, and the like, any derivativethereof, and any combination thereof.

In some embodiments, tackifiers suitable for use in conjunction with theanti-fog composition described herein may be food-grade tackifiers.Examples of food-grade tackifiers may, in some embodiments, include, butare not limited to, methylcellulose, ethylcellulose,hydroxyethylcellulose, carboxy methylcellulose, carboxy ethylcellulose,natural resins, natural rosins, and the like, and any combinationthereof.

Flame retardants suitable for use in conjunction with the anti-fogcomposition described herein may, in some embodiments, include, but arenot limited to, phosphates, catechol phosphates, resorcinol phosphates,aromatic polyhalides, and the like, and any combination thereof.

Antifungal agents suitable for use in conjunction with the anti-fogcomposition described herein may, in some embodiments, include, but arenot limited to, polyene antifungals, e.g., natamycin, rimocidin,filipin, nystatin, amphotericin B, candicin, and hamycin, imidazoleantifungals such as miconazole (available as MICATIN® from WellSpringPharmaceutical Corporation), ketoconazole (commercially available asNIZORAL® from McNeil consumer Healthcare), clotrimazole (commerciallyavailable as LOTRAMIN® and LOTRAMIN AF® available from Merck andCANESTEN® available from Bayer), econazole, omoconazole, bifonazole,butoconazole, fenticonazole, isoconazole, oxiconazole, sertaconazole(commercially available as ERTACZO® from OrthoDematologics),sulconazole, and tioconazole; triazole antifungals such as fluconazole,itraconazole, isavuconazole, ravuconazole, posaconazole, voriconazole,terconazole, and albaconazole), thiazole antifungals (e.g., abafungin),allylamine antifungals (e.g., terbinafine (commercially available asLAMISIL® from Novartis Consumer Health, Inc.), naftifine (commerciallyavailable as NAFTIN® available from Merz Pharmaceuticals), andbutenafine (commercially available as LOTRAMIN ULTRA® from Merck),echinocandin antifungals (e.g., anidulafungin, caspofungin, andmicafungin), polygodial, benzoic acid, ciclopirox, tolnaftate (e.g.,commercially available as TINACTIN® from MDS Consumer Care, Inc.),undecylenic acid, flucytosine, 5-fluorocytosine, griseofulvin,haloprogin, and any combination thereof.

Colorants, pigments, and dyes suitable for use in conjunction with theanti-fog composition described herein may, in some embodiments, include,but are not limited to, plant dyes, vegetable dyes, titanium dioxide,silicon dioxide, tartrazine, E102, phthalocyanine blue, phthalocyaninegreen, quinacridones, perylene tetracarboxylic acid di-imides,dioxazines, perinones disazo pigments, anthraquinone pigments, carbonblack, metal powders, iron oxide, ultramarine, nickel titanate,benzimidazolone orange gl, solvent orange 60, orange dyes, calciumcarbonate, kaolin clay, aluminum hydroxide, barium sulfate, zinc oxide,aluminum oxide, CARTASOL® dyes (cationic dyes, available from ClariantServices) in liquid and/or granular form (e.g., CARTASOL BrilliantYellow K-6G liquid, CARTASOL Yellow K-4GL liquid, CARTASOL Yellow K-GLliquid, CARTASOL Orange K-3GL liquid, CARTASOL Scarlet K-2GL liquid,CARTASOL Red K-3BN liquid, CARTASOL Blue K-5R liquid, CARTASOL Blue K-RLliquid, CARTASOL Turquoise K-RL liquid/granules, CARTASOL Brown K-BLliquid), FASTUSOL® dyes (an auxochrome, available from BASF) (e.g.,Yellow 3GL, Fastusol C Blue 74L), and the like, any derivative thereof,and any combination thereof. In some embodiments, when the colorant istitanium dioxide is utilized as the colorant, the titanium dioxide mayalso function to increase the stiffness of the film. In one embodiment,solvent dyes may be employed.

In some embodiments, colorants, pigments and dyes suitable for use inconjunction with the anti-fog composition described herein may befood-grade pigments and dyes. Examples of food-grade pigments and dyesmay, in some embodiments, include, but are not limited to, plant dyes,vegetable dyes, and the like, and any combination thereof.

Aroma agents, e.g., fragrances, suitable for use in conjunction with theanti-fog composition described herein may, in some embodiments, include,but are not limited to, spices, spice extracts, herb extracts, essentialoils, smelling salts, volatile organic compounds, volatile smallmolecules, methyl formate, methyl acetate, methyl butyrate, ethylacetate, ethyl butyrate, isoamyl acetate, pentyl butyrate, pentylpentanoate, octyl acetate, myrcene, geraniol, nerol, citral,citronellal, citronellol, linalool, nerolidol, limonene, camphor,terpineol, alpha-ionone, thujone, benzaldehyde, eugenol, isoeugenol,cinnamaldehyde, ethyl maltol, vanilla, vannillin, cinnamyl alcohol,anisole, anethole, estragole, thymol, furaneol, methanol, rosemary,lavender, citrus, freesia, apricot blossoms, greens, peach, jasmine,rosewood, pine, thyme, oakmoss, musk, vetiver, myrrh, blackcurrant,bergamot, grapefruit, acacia, passiflora, sandalwood, tonka bean,mandarin, neroli, violet leaves, gardenia, red fruits, ylang-ylang,acacia farnesiana, mimosa, tonka bean, woods, ambergris, daffodil,hyacinth, narcissus, black currant bud, iris, raspberry, lily of thevalley, sandalwood, vetiver, cedarwood, neroli, bergamot, strawberry,carnation, oregano, honey, civet, heliotrope, caramel, coumarin,patchouli, dewberry, helonial, bergamot, hyacinth, coriander, pimentoberry, labdanum, cassie, bergamot, aldehydes, orchid, amber, benzoin,orris, tuberose, palmarosa, cinnamon, nutmeg, moss, styrax, pineapple,bergamot, foxglove, tulip, wisteria, clematis, ambergris, gums, resins,civet, peach, plum, castoreum, civet, myrrh, geranium, rose violet,jonquil, spicy carnation, galbanum, hyacinth, petitgrain, iris,hyacinth, honeysuckle, pepper, raspberry, benzoin, mango, coconut,hesperides, castoreum, osmanthus, mousse de chene, nectarine, mint,anise, cinnamon, orris, apricot, plumeria, marigold, rose otto,narcissus, tolu balsam, frankincense, amber, orange blossom, bourbonvetiver, opopanax, white musk, papaya, sugar candy, jackfruit, honeydew,lotus blossom, muguet, mulberry, absinthe, ginger, juniper berries,spicebush, peony, violet, lemon, lime, hibiscus, white rum, basil,lavender, balsamics, fo-ti-tieng, osmanthus, karo karunde, white orchid,calla lilies, white rose, rhubrum lily, tagetes, ambergris, ivy, grass,seringa, spearmint, clary sage, cottonwood, grapes, brimbelle, lotus,cyclamen, orchid, glycine, tiare flower, ginger lily, green osmanthus,passion flower, blue rose, bay rum, cassie, African tagetes, Anatolianrose, Auvergne narcissus, British broom, British broom chocolate,Bulgarian rose, Chinese patchouli, Chinese gardenia, Calabrian mandarin,Comoros Island tuberose, Ceylonese cardamom, Caribbean passion fruit,Damascena rose, Georgia peach, white Madonna lily, Egyptian jasmine,Egyptian marigold, Ethiopian civet, Farnesian cassie, Florentine iris,French jasmine, French jonquil, French hyacinth, Guinea oranges, Guyanawacapua, Grasse petitgrain, Grasse rose, Grasse tuberose, Haitianvetiver, Hawaiian pineapple, Israeli basil, Indian sandalwood, IndianOcean vanilla, Italian bergamot, Italian iris, Jamaican pepper, Mayrose, Madagascar ylang-ylang, Madagascar vanilla, Moroccan jasmine,Moroccan rose, Moroccan oakmoss, Moroccan orange blossom, Mysoresandalwood, Oriental rose, Russian leather, Russian coriander, Sicilianmandarin, South African marigold, South American tonka bean, Singaporepatchouli, Spanish orange blossom, Sicilian lime, Reunion Islandvetiver, Turkish rose, Thai benzoin, Tunisian orange blossom,Yugoslavian oakmoss, Virginian cedarwood, Utah yarrow, West Indianrosewood, and the like, and any combination thereof.

Process for Producing the Anti-Fog Composition

In one embodiment, the invention relates to a process for producing theanti-fog composition disclosed herein. The process comprises the step ofcombining cellulose acetate, a plasticizer, an anti-blocking agent,e.g., an anti-blocking agent having an average particle size rangingfrom 0.02 microns to 6 microns, and solvent to form a dope, and casting,e.g., solvent casting, the dope to form the precursor film. The processfurther comprises the step of contacting the precursor film with acaustic solution to form a treated film. In one embodiment, thetreatment of the precursor film serves to partially or completelysaponify the precursor film, thus creating the desired (uniform ornon-uniform) degree of substitution, as discussed herein. The processfurther comprises the steps of washing the treated film to form a washedfilm and drying the washed film to form the primary film. The washing,in some embodiments, inhibits or eliminates the formation of salts onthe surface of the treated film. In one embodiment, the drying isachieved via oven drying. In one embodiment, the drying is achievedsimply via air drying.

In one embodiment, the process comprises the step of combining celluloseacetate, a plasticizer, and acetone to form the dope and casting, e.g.,solvent casting, the dope to form the precursor film. The resultantprimary film may comprise acetone, e.g., from 0.01 wt % to 3 wt %acetone. In such embodiments, the primary film may not necessarilycomprise anti-blocking agent having an average particle size rangingfrom 0.02 microns to 6 microns. This option is, of course, possiblehowever.

Processes for preparing cellulose acetate films have been described inU.S. Pat. Nos. 2,232,012 and 3,528,833, the entireties of which areincorporated by reference herein. In general, the solvent castingprocess comprises casting a mixture comprising plasticizer,anti-blocking agent, and cellulose acetate dissolved in a solvent, e.g.,acetone. The components of the mixture and the respective amountsdetermine the characteristics of the primary film, which is discussedherein.

In one embodiment, the mixture (dope) may be prepared by dissolvingcellulose acetate in a solvent. In some embodiments, the solvent isacetone. In one embodiment the solvent is selected from the groupconsisting of ethyl lactate methyl ethyl ketone, and dichlormethane. Toimprove the solubility of cellulose acetate in acetone, the celluloseacetate and acetone are preferably continuously added to a first mixer.The mixture may then be sent to a second and/or third mixer to allow forfull dissolution of the cellulose acetate in the acetone. The mixers maybe continuous mixers that are used in series. It is understood that insome embodiments, one mixer may be sufficient to achieve celluloseacetate dissolution. In other embodiments, two, three, or more mixers(e.g., four mixers, five mixers, or greater than five mixers) may beused in series or in parallel. In yet other embodiments, the celluloseacetate, solvent, and other additives may be combined in one or moreblenders, without the use of any mixers.

The mixture may further comprise a processing additive. Additionally,the mixture may comprise a colorant. The plasticizer may be addeddirectly to the first mixer or may be blended with at least a portion ofthe solvent and then added to the first mixer. Similarly, the colorant,anti-blocking agent and/or processing additive may be added directly tothe first mixer or may be combined with a portion of the solvent andthen added to the first mixer.

Once the cellulose acetate has been dissolved in the acetone solvent,the mixture may be referred to as dope. The dope may then be filtered toremove impurities. In some embodiments, the filtering is a two-stagefiltration.

In embodiments in which the dope is solution cast, the cellulose acetateis generally used in flake form. The (flake) cellulose acetate may thenbe dissolved in acetone to form an acetone dope. Additional components,including the plasticizers and the anti-blocking agent may be includedwith the acetone dope. The acetone dope may also comprise one or more ofanti-blocking agents, stearic acid, dyes and/or one or more specialtychemicals. The components are then mixed as described above. Theresultant mixture may then be filtered. The mixture then may be castinto a continuous film by die extrusion. The film may be dried in a warmair drying cabinet comprising rollers.

In one embodiment, after forming a mixture comprising cellulose acetate,plasticizer, and optional additives, the mixture may be melt extruded ina film die to form a sheet or melt extruded in a small hole die to formfilaments which are then sent to a pelletizer to form pellets. The meltextrusion may be performed at a temperature of up to 230° C., e.g., upto 220° C. or up to 210° C. A temperature greater than 230° C. may leadto destabilization of the mixture components, particularly of thecellulose acetate. The melt extruder may be a twin screw feeder withco-rotating screws, and may be operated at a screw speed from 100 to 500rpm, e.g., from 150 to 450 rpm, or from 250 to 350 rpm. The sheet mayhave a thickness between 0.5 and 0.6 mm, e.g., from 0.53 to 0.54 mm.

In one embodiment, the precursor film is formed via a melt extrusionprocess. The process for producing an anti-fog composition comprising aprimary film may comprise the step of extruding pellets comprisingcellulose acetate, a plasticizer, and optionally an anti-blocking agent.The anti-blocking agent, if utilized, may have an average particle sizeas discussed herein. In one embodiment, the anti-blocking agent isemployed when the desired thickness of the precursor film is less than300 microns, e.g., less than 200 microns. The pellets may furthercomprise an antioxidant and/or a heat stabilizer. The process furthercomprises the step of contacting the precursor film with a causticsolution to form a treated film. The process may further comprise thestep(s) of washing the treated film to form a washed film and/or dryingthe washed film to form the primary film.

One method to reduce the melting temperature of the cellulose acetate isto form a mixture comprising a plasticizer and the cellulose acetateprior to melt extrusion or solvent casting. In some embodiments, atleast one additive may also be mixed with the plasticizer and celluloseacetate to form the pellet mixture. The cellulose acetate may be presentin an amount from 75 to 98 wt. % of the mixture, e.g., from 80 to 97.5wt. % or from 85 to 95 wt. %. Weight percentages are based on the totalweight of the mixture, which includes the weight of the celluloseacetate, the plasticizer, and any additives included in the mixture. Asnoted above, the cellulose acetate may be provided as a flake or as apowder.

The pellet mixture may be formed by combining cellulose acetate, inflake or powder form, with plasticizer in a high speed mixer. In someembodiments, the plasticizer may be combined with the cellulose acetateusing a spray distribution system during the mixing step. In otherembodiments, the plasticizer may be added to the cellulose acetateduring the mixing step, either continuously or intermittently. In someembodiments, the flake form of cellulose acetate is preferred. Ifincluded in the mixture, the additives may be combined with thecellulose acetate and plasticizer during the mixing step. In someembodiments, the high speed mixer may be may be operated for 1 to 2minutes. In some embodiments, a base mixture may be prepared and thebase mixture may then be adjusted to obtain with additional plasticizerand/or additives.

In some embodiments when an extrusion process is utilized to form theprecursor film, antioxidants may, in some embodiments, mitigateoxidation and/or chemical degradation of the anti-fog compositiondescribed herein during storage, transportation, and/or implementation.Antioxidants suitable for use in conjunction with the anti-fogcomposition described herein may, in some embodiments, include, but arenot limited to, anthocyanin, ascorbic acid, glutathione, lipoic acid,uric acid, resveratrol, flavonoids, carotenes (e.g., beta-carotene),carotenoids, tocopherols (e.g., alpha-tocopherol, beta-tocopherol,gamma-tocopherol, and delta-tocopherol), tocotrienols, ubiquinol, gallicacids, melatonin, secondary aromatic amines, benzofuranones, hinderedphenols, polyphenols, hindered amines, organophosphorus compounds,thioesters, benzoates, lactones, hydroxylamines, and the like, and anycombination thereof. In one embodiment, the antioxidant may be selectedfrom the group consisting of stearyl3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate,bis(2,4-dicumylphenyl)pentaerythritol diphosphite,tris(2,4-di-tert-butylphenyl)phosphite, bisphenol A propoxylatediglycidyl ether, 9,10-dihydroxy-9-oxa-10-phosphaphenanthrene-10-oxideand combinations thereof.

In some embodiments, antioxidants suitable for use in conjunction withthe anti-fog composition described herein may be food-gradeantioxidants. Examples of food-grade antioxidants may, in someembodiments, include, but are not limited to, ascorbic acid, vitamin A,tocopherols, and the like, and any combination thereof.

In some melt extrusion-related embodiments, viscosity modifiers areemployed. Viscosity modifiers suitable for use in conjunction with theanti-fog composition described herein may, in some embodiments, include,but are not limited to, polyethylene glycols, and the like, and anycombination thereof, which, in some embodiments, may be a food-gradeviscosity modifier.

The caustic treatment may be achieved via a wide variety of methods. Anexemplary method is alkali saponification treatment. For example, seeInternational Patent Application No. WO 2008/029801, which isincorporated herein by reference. The caustic treatment alters thedegree of substitution of the precursor film, which, increases thehydrophilicity of the precursor film, and improves the anti-fogcharacteristics of the anti-fog composition. In one embodiment, thecaustic treatment substitutes one or more of the acetyl groups of thecellulose acetate with another substituent, e.g., a hydroxyl group, acarbonyl group, or a carboxylic acid group.

In one embodiment, the precursor film is submerged in a bath of causticsolution. In another embodiment, the precursor film is bonded to one ormore additional films, of the same or different composition, prior totreatment. As noted herein, multiple precursor layers may be formed andthen stacked upon one another, e.g., to achieve a thicker precursorfilm. The stacked precursor film may then be treated with causticsolution.

The caustic solution may comprise any suitable alkali solution, many ofwhich are known in the art. The caustic solution, in one embodiment,comprises an aqueous hydroxide solution. The caustic solution maycomprise from 5 wt % to 20 wt % alkali solution, e.g., from 5 wt % to 15wt % or from 7 wt % to 15 wt %. In some embodiments, the causticsolution comprises a potassium hydroxide solution present in the amountsdiscussed herein. The combination of the specific composition of theprecursor film and the caustic treatment advantageously provides for theanti-fog composition having the features described herein, e.g., theability absorb some water. In one embodiment, the caustic solutiontreatment step is conducted for a residence time ranging from 0.5minutes to 20 minutes, e.g., from 2 minutes to 10 minutes. In terms oflower limits, the caustic solution treatment step may be conducted for aresidence time greater than 0.5 minutes, e.g., greater than 2 minutes orgreater than 5 minutes. In terms of upper limits, the caustic solutiontreatment step may be conducted for a residence time less than 20minutes, e.g., less than 15 minutes or less than 10 minutes.

In one embodiment, the caustic solution treatment step is conducted at atemperature ranging from 40° C. to 100° C., e.g., from 45° C. to 75° C.,or 50° C. to 70° C. Generally speaking, hotter treatment temperaturesmay result in faster saponification. Treatment temperature, in somecases, is inversely proportional to the duration of the treatment. Interms of lower limits, the caustic solution treatment step may beconducted at a temperature greater than 40° C., e.g., greater than 45°C., greater than 50° C., or greater than 65° C. In terms of upperlimits, the caustic solution treatment step may be conducted at atemperature less than 100° C., e.g., less than 75° C., or less than 70°C.

The composition of the caustic solution may vary widely. In oneembodiment, the molarity of the caustic solution is from 0.1M to 25M,e.g., from 0.1M to 17.5M, from 2M to 10M, or from 2M to 2.5M. Variouscombinations of processing conditions, e.g., residence time,temperature, molarity, and caustic solution composition, arecontemplated. For example, in a preferred embodiment, the causticsolution comprises a 3M potassium hydroxide solution and the treatmentis performed at 60° C. for 5 or 10 minutes. In another embodiment, thecaustic solution comprises a 2.8M potassium hydroxide solution and thetreatment is performed at 72.1° C. for 20 minutes.

In one embodiment, the process comprises the step of contacting theprecursor film with acetone prior to saponifying. Without being bound bytheory, contacting the cellulose acetate precursor film with acetone mayopen up the pores of the film, soften the surface of the film, and/ormakes the film more porous, which advantageously provides for improved,faster saponification.

As noted above, the process further comprises the step of washing thetreated film, e.g., with water. The washing step may be achieved by anysuitable technique, many of which are known in the art. The washing stepwashes the surface of the treated film. In one embodiment, the washingis conducted at a temperature ranging from 0° C. to 50° C., e.g., from20° C. to 40° C. or from 25° C. to 35° C. In terms of lower limits, thewashing may be conducted at a temperature greater than 0° C., e.g.,greater than 20° C., or greater than 25° C. In terms of upper limits,the washing may be conducted at a temperature less than 50° C., e.g.,less than 40° C., or less than 35° C.

The process further comprises the step of drying the washed film to formthe primary film. The drying step may be achieved by any suitabletechnique, many of which are known in the art. In one embodiment, thedrying is achieved via oven drying. In one embodiment, the drying isachieved simply via air drying at ambient conditions. In one embodiment,the drying is conducted at a temperature ranging from 50° C. to 120° C.,e.g., from 50° C. to 100° C. or from 60° C. to 80° C. In terms of lowerlimits, the drying may be conducted at a temperature greater than 50°C., e.g., greater than 55° C., or greater than 60° C. In terms of upperlimits, the washing may be conducted at a temperature less than 120° C.,e.g., less than 100° C., or less than 80° C.

In one embodiment, the invention relates to a process for producing amulti-layer anti-fog film composition. The process comprises the step ofproviding a first anti-fog film comprising cellulose acetate, aplasticizer, and an anti-blocking agent (as discussed herein). Theprocess further comprises the steps of selecting a second filmcomposition based on a first preferred characteristic; and adhering thefirst anti-fog film composition to the second film composition to formthe multi-layer anti-fog film composition. The multi-layer anti-fog filmcomposition has enhanced characteristics. In one embodiment, the firstpreferred characteristic is improved hydrophilicity. The second film mayhave a second characteristic that synergistically complements thehydrophilicity or vice versa. For example the second characteristic maybe an anti-microbial characteristic. As another example, the secondcharacteristic may be film tinting of coloring. In some embodiments, thepreferred characteristic is selected such that the first anti-fogcomposition improves the preferred characteristic, e.g., creates asynergistic effect.

In one embodiment, the present invention relates to a consumer productcomposition comprising as one component thereof the anti-fog compositiondiscussed herein. Thus, in some cases, the consumer product compositioncomprises a consumer product and the anti-fog composition. In oneembodiment, the anti-fog composition will be attached to the consumerproduct. The methods for attachment will vary widely. In one embodiment,the consumer product will have a planar surface and the anti-fogcomposition will be disposed on, e.g., attached to, said planar surface.

The list of contemplated consumer products is vast. As one example, theconsumer product may be selected from the group consisting of lenses,windows, screens, glass structures, containers, appliances, plastic,optical devices, and visors. In one embodiment, the consumer product isa refrigerating device, e.g., a refrigerator, a cooler, or a freezer.The anti-fog composition may be adhered to the consumer product, e.g.,the planar surface of the consumer product, with an adhesive. Of course,the adhesive may vary widely and many suitable adhesives are known inthe art.

Broadly speaking, any consumer product that has a potential for moistureinteraction, e.g., humidity, fogging, dew accumulation, etc., may be aconsumable product suitable for use with the anti-fog compositions ofthe present invention.

Examples of other consumer products include, but are not limited to,furniture or components thereof, e.g., carpet and/or fabric coatedheadboards, chairs, and stools, picture frames, self-adhesive windowcoverings, e.g., decorative window stickers, window films, and windowtinting, light films, light filters, and the like.

In some embodiments, the consumer product includes bags, windows forboxes, wraps, camera lenses, windows, e.g., automotive windows, airplanewindows, televisions, any product that utilizes a glass or protectiveglass, e.g., windows or balcony enclosures.

Suitable substrates or surfaces (of consumer products) for use with theanti-fog composition described herein may, in some embodiments, comprisematerials that include, but are not limited to, ceramics, naturalpolymers, synthetic polymers, metals, natural materials, carbons, andthe like, and any combination thereof. Examples of ceramics may, in someembodiments, include, but are not limited to, glass, quartz, silica,alumina, zirconia, carbide ceramics, boride ceramics, nitride ceramics,and the like, and any combination thereof. Examples of natural polymersmay, in some embodiments, include, but are not limited to, cellulose,and the like, any derivative thereof, and any combination thereof.Examples of synthetic polymers may, in some embodiments, include, butare not limited to, cellulose diacetate, cellulose triacetate, syntheticbamboo, rayon, acrylic, aramid, nylon, polyolefins, polyethylene,polypropylene, polyesters, polyamides, zylon, and the like, anyderivative thereof, and any combination thereof. Examples of metals may,in some embodiments, include, but are not limited to, steel, stainlesssteel, aluminum, copper, and the like, any alloy thereof, and anycombination thereof. Examples of natural materials may, in someembodiments, include, but are not limited to, wood, grass, animal hide,and the like, and any combination thereof. Examples of carbons may, insome embodiments, include, but are not limited to, carbon fibers, andthe like, any derivative thereof, and any combination thereof.

Additional examples of substrates suitable for use in conjunction withthe articles described herein may, in some embodiments, include, but arenot limited to, wood and/or grass derived substrates, e.g., woodveneers, particle board, fiberboard, medium-density fiberboard,high-density fiberboard, oriented strand board, cork, hardwoods, e.g.,balsa wood, beech, ash, birch, Brazil wood, cherry, chestnut, elm,hickory, mahogany, maple, oak, rosewood, teak, walnut, locust, mango,alder, and the like, softwoods, e.g., pine, fir, spruce, cedar, hemlock,and the like, rough lumber, finished lumber, natural fibrous material,and bamboo, foam substrates, e.g., memory foams, polymer foams,polystyrene foam, polyurethane foam, frothed polyurethane, and soy-basedfoams, and the like, and any combination thereof.

The present invention is well adapted to attain the ends and advantagesmentioned as well as those that are inherent therein. The particularembodiments disclosed above are illustrative only, as the presentinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. Furthermore, no limitations are intended to thedetails of construction or design herein shown, other than as describedin the claims below. It is therefore evident that the particularillustrative embodiments disclosed above may be altered, combined, ormodified and all such variations are considered within the scope andspirit of the present invention. The invention illustratively disclosedherein suitably may be practiced in the absence of any element that isnot specifically disclosed herein and/or any optional element disclosedherein. While compositions and methods are described in terms of“comprising,” “containing,” or “including” various components or steps,the compositions and methods can also “consist essentially of” or“consist of” the various components and steps. All numbers and rangesdisclosed above may vary by some amount. Whenever a numerical range witha lower limit and an upper limit is disclosed, any number and anyincluded range falling within the range is specifically disclosed. Inparticular, every range of values (of the form, “from about a to aboutb,” or, equivalently, “from approximately a to b,” or, equivalently,“from approximately a-b”) disclosed herein is to be understood to setforth every number and range encompassed within the broader range ofvalues. Also, the terms in the claims have their plain, ordinary meaningunless otherwise explicitly and clearly defined by the patentee.Moreover, the indefinite articles “a” or “an,” as used in the claims,are defined herein to mean one or more than one of the element that itintroduces. If there is any conflict in the usages of a word or term inthis specification and one or more patent or other documents that may beincorporated herein by reference, the definitions that are consistentwith this specification should be adopted.

The following embodiments are contemplated. All combinations of featuresand embodiments are contemplated.

Embodiment 1: An anti-fog composition, comprising a primary film havingopposing major planar surfaces and a central coplanar region disposedbetween said opposing major planar surfaces, said primary filmcomprising cellulose acetate, plasticizer, and an anti-blocking agenthaving an average particle size ranging from 0.02 microns to 6 microns,wherein the cellulose acetate has a degree of substitution thatincreases from the opposing major planar surfaces toward the centralcoplanar region.

Embodiment 2: An anti-fog composition, comprising a primary film havingopposing major planar surfaces and a central coplanar region disposedbetween said opposing major planar surfaces and comprising celluloseacetate, plasticizer, and an anti-blocking agent having an averageparticle size ranging from 0.02 microns to 6 microns, wherein theanti-fog composition has a fog time greater than 10 seconds, preferablygreater than 20 seconds, more preferably greater than 30 seconds.

Embodiment 3: An anti-fog composition, comprising a primary film havingopposing major planar surfaces and a central coplanar region disposedbetween said opposing major planar surfaces and comprising celluloseacetate, a plasticizer, and an anti-blocking agent, wherein the anti-fogcomposition has a fog time greater than 10 seconds, preferably greaterthan 20 seconds, more preferably greater than 30 seconds; wherein theanti-fog composition has a haze value ranging from 0.1% to 4.0%,preferably from 0.1% to 2.0%, as measured by ASTM D1003.

Embodiment 4: An anti-fog composition, comprising a primary film havingopposing major planar surfaces and a central coplanar region disposedbetween said opposing major planar surfaces and comprising a mixture of:

cellulose acetate

a phthalate plasticizer; and

an anti-blocking agent having an average particle size ranging from 0.02microns to 6 microns, wherein the anti-fog composition has a water vaportransmission rate greater than 100.

Embodiment 5: An anti-fog composition, comprising a primary film havingopposing major planar surfaces and a central coplanar region disposedbetween said opposing major planar surfaces and comprising a mixture ofcellulose acetate, diethyl phthalate, and an anti-blocking agentcomprising silica and having an average particle diameter ranging from0.02 microns to 6 microns, wherein the anti-fog composition has a fogtime greater than 10 seconds, preferably greater than 20 seconds, morepreferably greater than 30 seconds.

Embodiment 6: An anti-fog composition, comprising a primary film havinga thickness, opposing major planar surfaces and a central coplanarregion disposed between the opposing major planar surfaces, the primaryfilm comprising cellulose acetate, plasticizer, and an anti-blockingagent having an average particle size less than 6 microns, wherein thedegree of substitution throughout the thickness of the primary film issubstantially uniform.

Embodiment 7: An anti-fog composition, comprising a primary film havingopposing major planar surfaces and a central coplanar region disposedbetween said opposing major planar surfaces, said primary filmcomprising cellulose acetate, plasticizer, and from 0.01 wt % to 3 wt %acetone.

Embodiment 8: An anti-fog composition, comprising a primary film havingopposing major planar surfaces and a central coplanar region disposedbetween said opposing major planar surfaces, said primary filmcomprising cellulose acetate, plasticizer, and an anti-blocking agenthaving an average particle size ranging from 0.02 microns to 6 microns.

Embodiment 9: The embodiment of any one of embodiments 1-5, 7 and 8,having a degree of substitution at the opposing major planar surfaces ofabout zero.

Embodiment 10: The embodiment of any one of embodiments 1-9, having adegree of substitution at the central coplanar region from 2.0 to 2.6,preferably from 2.2 to 2.55.

Embodiment 11: The embodiment of any one of embodiments 1-10, 51 and 52,having a fog time greater than 10 seconds, preferably greater than 20seconds, more preferably greater than 30 seconds.

Embodiment 12: The embodiment of any one of embodiments 1-11, 51 and 52,having a haze value ranging from 0.1% to 4.0%, preferably from 0.1% to2.0%, as measured by ASTM D1003.

Embodiment 13: The embodiment of any one of embodiments 1-3, 6-12, 51and 52, wherein the plasticizer is selected from the group consisting of1,2,3-triacetoxypropane (triacetin), tributyl citrate, triethyl citrate,triphenyl phosphate, tris(chlorisopropyl)phosphate, dimethyl phthalate,bornan-2-one, PEG-DGE, PPG-DGE, tributyl phosphate, and combinationsthereof.

Embodiment 14: The embodiment of any one of embodiments 1-4, 6-13, 51and 52, wherein the plasticizer comprises diethyl phthalate.

Embodiment 15: The embodiment of any one of embodiments 1-4, 6, 8-14, 51and 52, wherein the anti-blocking agent comprises silica.

Embodiment 16: The embodiment of any one of embodiments 1-6 and 8-15,wherein the primary film comprises from 60 wt % to 95 wt % celluloseacetate, from 5 to 40 wt. % plasticizer and from 0.01 to 10 wt. %anti-blocking agent.

Embodiment 17: The embodiment of any one of embodiments 1-16, whereinthe primary film further comprises a releasing agent.

Embodiment 18: The embodiment of any one of embodiments 1-6 and 8-17,wherein the anti-blocking agent has an average particle size less than 3microns, preferably less than 1 micron or from 0.02 to 1 micron.

Embodiment 19: The embodiment of any one of embodiments 1-18, 51 and 52,wherein the anti-fog composition has a thickness ranging from 25 micronsto 2000 microns.

Embodiment 20: The embodiment of any one of embodiments 1-19, 52 and 52,wherein the anti-fog composition is in the form of a rolled sheet.

Embodiment 21: The embodiment of any one of embodiments 1-20 and 52,wherein the anti-fog composition does not comprise discrete layers.

Embodiment 22: The embodiment of any one of embodiments 1-21, 51 and 52,further comprising a protective film adhered to one of the major planarsurfaces.

Embodiment 23: The embodiment of embodiment 22, wherein the protectivefilm comprises a protective material selected from polyesters,polyethylenes, and polyethylene terephthalate, and wherein theprotective film is adhered to at least one of the major planar surfaceswith an adhesive.

Embodiment 24: The embodiment of any one of embodiments 22 and 23,further comprising an adhesive layer disposed on the other of the majorplanar surfaces of the primary film.

Embodiment 25: The embodiment of any one of embodiments 1-24, furthercomprising a secondary film adhered to the primary film and havingsubstantially the same composition as the primary film.

Embodiment 26: The embodiment of any one of embodiments 1-24, furthercomprising a secondary film adhered to the primary film and having acomposition different from the primary film.

Embodiment 27: The embodiment of any one of embodiments 1-24 or 26,wherein the secondary film comprises cellulose acetate, wherein thecellulose acetate in the secondary film has a degree of substitutiongreater than the degree of substitution of the primary film.

Embodiment 28: A consumer product having a planar surface and thecomposition of any one of embodiments 1-27, 51 and 52, disposed on saidplanar surface.

Embodiment 29: The embodiment of embodiment 28, wherein the consumerproduct is selected from the group consisting of lenses, windows,screens, glass structures, containers, appliances, plastic, opticaldevices, and visors.

Embodiment 30: The embodiment of embodiment 28, wherein the consumerproduct is a refrigerating device.

Embodiment 31: The embodiment of any one of embodiments 28-30, whereinthe anti-fog composition is adhered to said planar surface with anadhesive.

Embodiment 32: A process for producing an anti-fog compositioncomprising a primary film, the process comprising the steps of:

(a) combining cellulose acetate, a plasticizer, a anti-blocking agenthaving an average particle size ranging from 0.02 microns to 6 micronsand solvent to form a dope;

(b) casting the dope to form a precursor film

(c) contacting the precursor film with a caustic solution to form atreated film;

(d) washing the treated film to form a washed film; and

(e) drying the washed film to form the primary film.

Embodiment 33: The embodiment of embodiment 32, wherein the primary filmhas opposing major planar surfaces and a central coplanar regiondisposed between said opposing major planar surfaces, wherein saidcellulose acetate has a degree of substitution that increases from theopposing major planar surfaces toward the central coplanar region.

Embodiment 34: The embodiment of any one of embodiments 32, 33, and 52,further comprising the step of treating the precursor film with acetoneprior to the contacting step.

Embodiment 35: The embodiment of any one of embodiments 32-34, whereinthe precursor film has a degree of substitution ranging from 2.0 to 2.6,preferably from 2.2 to 2.55.

Embodiment 36: The embodiment of any one of embodiments 32-35, whereinthe dope comprises cellulose acetate flake.

Embodiment 37: The embodiment of any one of embodiments 32-36 and 52,wherein the caustic solution comprises an aqueous hydroxide solution.

Embodiment 38: The embodiment of any one of embodiments 32-37 and 52,wherein the caustic solution comprises a 5 to 20 wt. % potassiumhydroxide solution.

Embodiment 39: The embodiment of any one of embodiments 32-38 and 52,wherein the contacting is conducted for a residence time ranging from0.5 minutes to 20 minutes, preferably from 2 minutes to 10 minutes.

Embodiment 40: The embodiment of any one of embodiments 32-39 and 52,wherein the contacting is conducted at a temperature ranging from 40° C.to 100° C.

Embodiment 41: The embodiment of any one of embodiments 32-40 and 52,wherein the washing is conducted at a temperature ranging from 0° C. to50° C.

Embodiment 42: The embodiment of any one of embodiments 32-41 and 52,wherein the drying is conducted at a temperature ranging from 50° C. to120° C.

Embodiment 43: The embodiment of any one of embodiments 32-42, 51 and52, wherein the anti-fog composition has a fog time greater than 10seconds, preferably greater than 20 seconds, more preferably greaterthan 30 seconds.

Embodiment 44: The embodiment of any one of embodiments 32-43, 51 and52, wherein the anti-fog composition has a haze value ranging from 0.1%to 4.0%, preferably from 0.1% to 2.0% as measured by ASTM D1003.

Embodiment 45: A process for producing a multi-layer anti-fog filmcomposition, comprising the steps of:

providing a first anti-fog film composition comprising

-   -   a cellulose acetate    -   a plasticizer; and    -   an anti-blocking agent having an average particle diameter        ranging from 0.02 microns to 6 microns; and

selecting a second film composition based on a first preferredcharacteristic; and

adhering the first anti-fog film composition to the second filmcomposition to form the multi-layer anti-fog film composition havingenhanced characteristics.

Embodiment 46: The embodiment of embodiment 45, wherein the preferredcharacteristic is selected such that the first anti-fog compositionimproves the preferred characteristic.

Embodiment 47: A multi-layer anti-fog composition, comprising:

a primary film having opposing major planar surfaces and a centralcoplanar region disposed between the opposing major planar surfaces andcomprising cellulose acetate having a first degree of substitution lessthan 2.6; and

a secondary film having opposing major planar surfaces and a centralcoplanar region disposed between the opposing major planar surfaces, oneof the opposing major surfaces of the secondary film being adhered toone of the opposing major planar surfaces of the primary film, thesecondary film comprising cellulose acetate having a second degree ofsubstitution greater than the first degree of substitution.

Embodiment 48: The embodiment of embodiment 47, further comprising anadditional film adhered to the other of the opposing major planarsurfaces of the secondary film.

Embodiment 49: The embodiment of embodiment 48, wherein the additionalfilm has opposing major planar surfaces and a central coplanar regiondisposed between the opposing major planar surfaces and wherein one ofthe opposing major surfaces is adhered to the other of the opposingmajor planar surfaces of the secondary film.

Embodiment 50: The embodiment of embodiment 49, wherein the additionalfilm comprises cellulose acetate having a degree of substitution greaterthan the second degree of substitution.

Embodiment 51: A multi-layer anti-fog composition, comprising:

a first primary film having opposing major planar surfaces and a centralcoplanar region disposed between the opposing major planar surfaces andcomprising cellulose acetate, plasticizer, and an anti-blocking agent,optionally silica, having an average particle size ranging from 0.02microns to 6 microns, wherein the cellulose acetate has a degree ofsubstitution that increases from the opposing major planar surfacestoward the central coplanar region;

a secondary film, optionally comprising a single film or multipleadhered films of same or different compositions, having opposing majorplanar surfaces and a central coplanar region disposed between theopposing major planar surfaces, one of the opposing major surfaces ofthe secondary film being adhered to one of the opposing major planarsurfaces of the first primary film, the secondary film optionally havinga substantially uniform degree of substitution about its cross-sectionalthickness; and

a second primary film having opposing major planar surfaces and acentral coplanar region disposed between the opposing major planarsurfaces and comprising cellulose acetate, plasticizer, and ananti-blocking agent, optionally silica, having an average particle sizeranging from 0.02 microns to 6 microns, wherein the cellulose acetatehas a degree of substitution that increases from the opposing majorplanar surfaces toward the central coplanar region,

wherein the other of the opposing major surfaces of the secondary filmis adhered to one of the opposing major planar surfaces of the secondprimary film.

Embodiment 52: A process for producing an anti-fog compositioncomprising a primary film, the process comprising the steps of:

(a) extruding pellets comprising cellulose acetate, a plasticizer, andoptionally an anti-blocking agent having an average particle sizeranging from 0.02 microns to 6 microns, and optionally an antioxidantand/or a heat stabilizer, to form a precursor film, preferably having athickness less than 300 microns, more preferably less than 200 microns;

(b) contacting the precursor film with a caustic solution to form atreated film;

(c) washing the treated film to form a washed film; and

(d) drying the washed film to form the primary film.

Examples

Sample anti-fog compositions were prepared using a solvent castingmethod. Dope Solutions 1-8 utilized the components and weightpercentages shown in Table 1. The particle size of the silicaanti-blocking agent ranged from 0.02 microns to 6 microns.

TABLE 1 Dope Solutions Dope Solution 1 Cellulose Acetate Standard Flake100 parts Plasticizer diethyl phthalate 27 parts Anti-Blocking Agentsilica (<6 μm) ~0.1 part Additional Additives — — Dope Solution 2Cellulose Acetate Standard Flake 100 parts Plasticizer 7TA + 3 TPP 10parts Anti-Blocking Agent silica (<6 μm) ~0.1 part Additional Additivesacetone UV additive ~0.1 part Dope Solution 3 Cellulose Acetate StandardFlake 100 parts Plasticizer TPP 8 parts Anti-Blocking Agent silica (<6μm) ~0.1 part Additional Additives UV additive ~0.1 part Dope Solution 4Cellulose Acetate Pulp Type I 100 parts Plasticizer diethyl phthalate 27parts Anti-Blocking Agent silica (<6 μm) ~0.1 part Additional Additives— Dope Solution 5 Cellulose Acetate Vendor 3 Pulp Type II 100 partsPlasticizer diethyl phthalate 27 parts Anti-Blocking Agent silica (<6μm) ~0.1 part Additional Additives — Dope Solution 6 Cellulose AcetateStandard Flake 100 parts Plasticizer TCPP 20 parts Anti-Blocking Agentsilica (<6 μm) ~0.1 parts Additional Additives — — Dope Solution 7Cellulose Acetate Standard Flake 100 parts Plasticizer 5TA + 5 TPP 10parts Anti-Blocking Agent silica (<6 μm) ~0.1 parts Additional AdditivesUV additive ~0.1 parts Dope Solution 8 Cellulose Acetate Standard FlakePlasticizer TPP 10 parts Anti-Blocking Agent silica (<6 μm) ~0.1 partsAdditional Additives acetone UV additive ~0.1 parts

Dope Solutions 1-8 were solvent cast to form the respective precursorfilms. The precursor films were divided into samples (some with varyingthicknesses) and the respective samples were submerged in a causticsolution and treated as shown in Table 2. The treated samples were thenwashed with water for a predetermined time and oven dried at 50° C.

The samples were tested for haze value using ASTM D1003 and fog timeusing the test disclosed herein. The results are shown in Table 2. Hazevalues were measured initially and after a predetermined period of time.The measurements shown below reflect the final haze values. In someembodiments, differences in thickness may account for differing fogand/or haze values in cases where similar treatments were employed.

TABLE 2 Process Conditions and Test Results Caustic Treatment TreatmentAnti-fog Th. Solution Temperature Time time Haze Sample Form. (gauge)(wt. %) (° C.) (minutes) (seconds) (%) 1 1 360 KOH; 12.3% 70 5  60 0.7 21 360 KOH; 12.3% 70 10  80 0.7 3 1 360 KOH; 12.3% 60 5  40 0.4 4 1 360KOH; 12.3% 60 10  90 0.4 5 1 360 KOH; 12.3% 60 5  50 0.4 6 1 360 KOH;12.3% 70 10  90 0.5 7 1 360 KOH; 12.3% 65 5  40 0.5 8 1 360 KOH; 12.3%60 5  25 0.5 9 1 75 KOH; 12.3% 60 5  70 0.7 10 1 75 KOH; 12.3% 60 5  700.7 11 1 75 KOH; 12.3% 60 10 120 0.7 12 1 75 KOH; 12.3% 60 10 120 0.7 131 540 KOH; 16.4% 65 10  70 0.8 14 1 540 KOH; 16.4% 65 10  70 0.8 15 1540 KOH; 16.4% 65 10  80 0.8 16 1 540 KOH; 16.4% 65 7  43 0.8 17 1 540KOH; 16.4% 65 7  45 0.8 18 1 540 KOH; 16.4% 65 7  45 0.8 19 1 360 KOH;12.4% 30 5.8  52 0.9 20 1 360 KOH; 12.4% 30 7  84 1.0 21 1 360 KOH;12.4% 30 6.4  75 0.8 22 1 360 KOH; 13.1% 30 6.4  90 0.8 23 1 360 KOH;13.1% 30 6.4  55 0.8 24 1 180 KOH; 13.1% 30 6.4  69 0.9 25 1 180 KOH;13.1% 30 3.8  57 0.6 26 1 75 KOH; 13.1% 30 6.4 — — 27 1 75 KOH; 13.1% 303.5  64 0.4 28 1 75 KOH; 13.1% 30 3.0  76 0.4 29 1 75 KOH; 13.1% 30 3.5 64 0.4 30 1 360 KOH; 16.0% 30 5.8 102 1.0 31 1 290 KOH; 10.3% 60 10  500.8 32 1 310 KOH; 10.3% 60 10  45 0.9 33 1 300 KOH; 14.3% 60 10  67 0.834 1 360 KOH; 12.3% 70 5  60 0.7 35 1 360 KOH; 12.3% 70 10  80 0.7 36 1360 KOH; 12.3% 60 5  40 0.4 37 1 360 KOH; 12.3% 60 10  90 0.4 38 1 360KOH; 12.3% 60 5  50 0.4 39 1 360 KOH; 12.3% 70 10  90 0.5 40 1 360 KOH;12.3% 65 5  40 0.5 41 1 360 KOH; 12.3% 60 5  25 0.5 42 1 75 KOH; 12.3%60 5  70 0.7 43 1 75 KOH; 12.3% 60 5  70 0.7 44 1 75 KOH; 12.3% 60 10120 0.7 45 1 75 KOH; 12.3% 60 10 120 0.7 46 1 540 KOH; 16.4% 65 10  700.8 47 1 540 KOH; 16.4% 65 10  70 0.8 48 1 540 KOH; 16.4% 65 10  80 0.849 1 540 KOH; 16.4% 65 7  43 0.8 50 1 540 KOH; 16.4% 65 7  45 0.8 51 1540 KOH; 16.4% 65 7  45 0.8 52 1 300 KOH; 12.3% 60 10  60 2.0 53 1 300KOH; 12.3% 60 8  50 2.0 54 2 350 KOH; 16.3% 70 15    90+ 1.4 55 3 525NaOH; 6.5% 61 20  21 1.6 56 3 525 NaOH; 6.5% 72 20  23 1.6 57 3 525NaOH; 7.0 % 50 20  24 1.6 58 3 525 KOH; 15.0% 60 20  51 1.8 59 3 525KOH; 16.8% 72.1 20  70 1.0 60 3 525 KOH; 16.8% 72.1 20  80 1.0 61 3 525KOH; 16.8% 72.1 20  80 1.0 62 3 525 NaOH; 6.3% 51 20  18 1.7 63 3 525NaOH; 6.3% 72 10  11 1.3 64 3 525 NaOH; 7% 51 10  13 2.0 65 3 525 NaOH;7% 60 20  20 2.1 66 3 525 NaOH; 7% 62 10  11 1.7 67 3 525 NaOH; 7% 72 20 31 3.6 68 3 525 NaOH; 7% 71 10  14 1.3 69 3 525 NaOH; 7.7% 52 20  192.6 70 3 525 NaOH; 7.7% 52 10  11 1.1 71 3 525 NaOH; 7.7% 61 20  26 3.772 3 525 NaOH; 7.7% 73 10  13 1.9 73 3 525 NaOH; 7% 71 20  28 3.8 74 3525 NaOH; 7% 71 10  17 2.4 75 3 525 NaOH; 7% 72 10  14 2.2 76 3 525 KOH;17.5% 70 10  11 2.3 77 3 525 KOH; 15% 60 20  43 2.1 78 3 525 KOH; 17.5%62.7 15  40 2.4 79 3 525 KOH; 17.5% 62.6 20  39 2.3 80 3 525 KOH; 17.5%72.2 15  31 2.2 81 3 525 KOH; 17.5% 70 15  60 3.8 82 3 525 KOH; 17.5% 7015  60 3.5 83 3 525 KOH; 16% 70 15  42 3.1 84 3 525 KOH; 16% 70 15  382.2 85 3 525 KOH; 16% 70 10  14 1.3 86 3 525 KOH; 16% 60 20  39 2.5 87 3525 KOH; 16% 60 20  17 3.0 88 4 280 KOH; 10.3% 60 10  40 0.7 89 4 300KOH; 10.3% 60 11  36 0.6 90 4 300 KOH; 10.3% 60 10  40 0.6 91 4 300 KOH;14.3% 60 11  52 0.7 92 4 70 KOH; 10.3% 60 10  90 0.7 93 4 500 KOH; 10.3%60 10  36 0.8 94 4 500 KOH; 10.3% 60 10  34 0.4 95 5 315 KOH; 10.3% 6010  43 1.4 96 5 315 KOH; 10.3% 60 10  26 1.7 97 6 230 KOH; 12.3% 60 10 60 1.1 98 6 250 KOH; 12.3% 60 10 120 1.4 99 7 250 KOH; 16.3% 70 15   90+ 3.0 100 8 300 KOH; 16% 70 15  54 2.3

The test results shown in Table 2 demonstrate that desirable anti-fogcompositions having high anti-fog times, e.g., greater than 20 seconds,and low haze values, e.g., less than 1.5, surprisingly and unexpectedlymay be prepared by treating with a caustic solution precursor filmsformed from a dope comprising cellulose acetate, plasticizer andsmall-particle anti-blocking agent.

Comparative Examples

Sample anti-fog compositions were prepared using the casting method.Comparative Dope Solutions A and B utilized the components and weightpercentages shown in Table 3. The particle size of the silica (largeparticles) was greater than 6 microns.

TABLE 3 Comparative Dope Solutions Comparative Dope Solution A CelluloseAcetate Standard Flake 100 parts Plasticizer diethyl phthalate 27 partsAnti-Blocking Agent silica (>6 μm) ~0.1 part Additional Additives — —Comparative Dope Solution B Cellulose Acetate Standard Flake 100 partsPlasticizer 7TA + 3 TPP 24 parts Anti-Blocking Agent silica (>6 μm) ~0.1part Additional Additives — —

Comparative Dope Solutions A and B were solvent cast to form respectiveprecursor films. The precursor films were divided into samples (somewith varying thicknesses) and the respective samples were submerged in acaustic solution and treated as shown in Table 4. The treated sampleswere then washed with water for a predetermined time and oven dried at50° C.

The samples were tested for haze value using ASTM D1003 and fog timeusing the test discussed herein. The results are shown in Table 4. Hazevalues were measured initially and after a predetermined period of time.The measurements shown below reflect the final haze values. In someembodiments, differences in thickness may account for differing fogand/or haze values in cases where similar treatments were employed.

TABLE 4 Process Conditions and Test Results Caustic Treatment TreatmentAnti-fog Th. Solution Temperature Time time, Haze Sample Form. (gauge)(wt %) (° C.) (minutes) (seconds) (%) A1 A 350 KOH; 10.3% 40 10 21 8.7A2 A 350 KOH; 10.3% 42 10 19 8.5 A3 A 350 KOH; 10.3% 35 10 20 7.9 A4 A350 KOH; 10.3% 30 15 44 8.7 A5 A 350 KOH; 10.3% 30 20 46 10.2 A6 A 350KOH; 10.3% 40 15 46 10.3 A7 A 350 KOH; 10.3% 40 20 48 9.8 A8 A 350 KOH;10.3% 30 10 12 8.3 A9 A 350 KOH; 10.3% 30 10 13 8.5 A10 A 350 KOH; 10.3%30 15 15 8.4 A11 A 350 KOH; 10.3% 40 20 23 9.1 A12 A 350 KOH; 10.3% 4015 25 8.6 A13 A 350 KOH; 10.3% 30 20 42 9.1 A14 A 350 KOH; 10.3% 35 1016 8.4 A15 A 350 KOH; 10.3% 35 20 27 9 A16 A 350 KOH; 10.3% 60 10 48 9.3A17 A 350 KOH; 10.3% 60 10 60 9.2 A18 A 350 KOH; 10.3% 60 15 88 9.5 A19A 350 KOH; 20.5% 41 20 14 13 A20 A 350 KOH; 20.5% 42 20 16 13.1 A21 A350 KOH; 20.5% 37 15 10 9.8 A22 A 350 KOH; 20.5% 40 15 11 10.7 A23 A 350KOH; 20.5% 41 10 7 9.1 A24 A 350 KOH; 20.5% 41 10 8 9.1 A25 A 350 KOH;20.5% 41 5 6 8.6 A26 A 350 KOH; 20.5% 40 5 8 7.6 A27 A 350 KOH; 20.5% 6020 120 11.1 A28 A 350 KOH; 20.5% 61 20 127 11.5 A29 A 350 KOH; 20.5% 6215 115 10.7 A30 A 350 KOH; 20.5% 61 15 103 11.2 A31 A 350 KOH; 20.5% 615 34 11.1 A32 A 350 KOH; 20.5% 61 5 38 10.6 A33 A 350 KOH; 20.5% 62 1093 10.6 A34 A 350 KOH; 20.5% 61 10 80 9.6 A35 A 350 NaOH; 7.0% — — 0.56.3 A36 A 350 NaOH; 7.0% 30 10 3 9.2 A37 A 350 NaOH; 7.0% 31 10 3 9.2A38 A 350 NaOH; 7.0% 30 20 6 10.6 A39 A 350 NaOH; 7.0% 31 20 7 10.5 A40A 350 NaOH; 7.0% 36 20 5 10.8 A41 A 350 NaOH; 7.0% 40 20 14 9.6 A42 A350 NaOH; 7.0% 31 15 5 10.0 A43 A 350 NaOH; 7.0% 32 15 6 9.1 A44 A 350NaOH; 7.0% 34 10 5 8.5 A45 A 350 NaOH; 7.0% 36 10 6 8.5 A46 A 350 NaOH;7.0% 36 20 9 9.8 A47 A 350 NaOH; 7.0% 39 15 13 9.3 A48 A 350 NaOH; 7.0%41 15 11 8.8 A49 A 350 NaOH; 7.0% 40 20 13 9.5 A50 A 350 KOH; 10.3% 3015 44 6.3 A51 A 350 KOH; 10.3% 30 20 46 6.3 A52 A 350 KOH; 10.3% 40 1546 6.3 A53 A 350 KOH; 10.3% 40 20 48 6.3 A54 A 350 KOH; 10.3% 30 20 426.3 A55 A 350 KOH; 10.3% 60 10 48 6.3 A56 A 350 KOH; 10.3% 60 10 60 6.3A57 A 350 KOH; 10.3% 60 15 88 6.3 A58 A 360 KOH; 10.3% 32 11 24 6.0 A59A 360 KOH; 10.3% 31 15 25 6.1 A60 A 360 KOH; 10.3% 40 12 21 6.0 A61 A360 KOH; 10.3% 40 15 36 6.0 A62 A 360 KOH; 10.3% 48 16 56 5.9 A63 A 360KOH; 10.3% 49 10 28 6.0 A64 A 360 KOH; 10.3% 60 10 84 6.0 A65 A 360 KOH;10.3% 60 15 97 6.1 A66 A 360 KOH; 10.3% 60 10 — 6.0 A67 A 360 KOH; 10.3%47 15 55 6.0 A68 A 360 KOH; 10.3% 48 15 48 5.9 A69 A 360 KOH; 10.3% 5015 56 6.0 A70 A 360 KOH; 10.3% 50 15 56 6.0 A71 A 360 KOH; 10.3% 50 1590 6.0 A72 A 360 KOH; 10.3% 60 15 101 6.0 A73 A 360 KOH; 10.3% 60 10 635.9 A74 A 360 KOH; 10.3% 60 10 68 6.0 A75 A 360 KOH; 10.3% 60 10 2 6.0A76 A 360 KOH; 10.3% 60 10 2 6.0 A77 A 360 KOH; 10.3% 60 10 32 5.9 A78 A360 KOH; 10.3% 60 15 77 6.0 A79 A 360 KOH; 10.3% 60 10 46 5.9 A80 A 360KOH; 12.3% 60 10 80 5.9 A81 A 360 KOH; 12.3% 60 10 48 5.9 A82 A 500 KOH;12.3% 60 10 70 4.1 A83 A 500 KOH; 12.3% 60 10 30 4.1 A84 A 360 KOH;12.3% 40 10 14 5.9 A85 A 360 KOH; 12.3% 40 10 12 5.9 A86 A 360 KOH;12.3% 60 10 40 5.9 A87 A 360 KOH; 12.3% 60 10 70 5.9 A88 A 360 KOH;12.3% 60 10 80 5.9 A89 A 360 KOH; 12.3% 60 10 80 5.9 A90 A 360 KOH;12.3% 60 10 65 5.9 A91 A 360 KOH; 12.3% 60 10 90 5.6 A92 A 360 KOH;12.3% 60 10 80 5.6 A93 A 360 KOH; 12.3% 60 10 90 5.6 A94 A 360 KOH;12.3% 60 10 96 5.6 A95 A 360 KOH; 12.3% 60 10 80 5.6 A96 A 360 KOH;12.3% 40 5 10 5.6 A97 A 360 KOH; 12.3% 40 5 10 5.6 A98 A 360 KOH; 12.3%40 5 10 5.6 A99 A 360 KOH; 12.3% 45 10 16 5.8 A100 A 360 KOH; 12.3% 4515 28 5.8 A101 A 360 KOH; 12.3% 45 10 19 5.8 A102 A 360 KOH; 12.3% 60 1064 5.8 A103 A 360 KOH; 12.3% 60 10 70 5.8 A104 A 360 KOH; 12.3% 60 10 605.8 A105 A 360 KOH; 12.3% 60 10 80 5.8 A106 A 360 KOH; 12.3% 60 10 825.8 A107 A 360 KOH; 12.3% 60 10 90 5.8 A108 A 360 KOH; 12.3% 60 10 885.8 A109 A 360 KOH; 12.3% 60 5 45 5.8 A110 A 360 KOH; 12.3% 60 5 60 5.8A111 A 360 KOH; 12.3% 60 5 60 5.8 B1 B 360 — — — 0.5 4.2 B2 B 360 NaOH;7.0% 40 5 — 4.2 B3 B 360 NaOH; 7.0% 40 5 — 4.1 B4 B 360 NaOH; 2.4% 35 5— 4.1 B5 B 360 NaOH; 2.4% 35 2.5 — 4.2 B6 B 360 NaOH; 2.4% 35 0.5 2 4.2B7 B 360 NaOH; 1.9% 30 2 3 4.2 B8 B 360 NaOH; 1.9% 30 5 — 4.2 B9 B 360NaOH; 1.9% 30 3 — 4.1 B10 B 360 NaOH; 1.9% 30 2.5 — 4.2 B11 B 360 NaOH;1.9% 40 2 — 4.2 B12 B 360 NaOH; 1.9% 40 1 5 4.2

The test results shown in Table 4 demonstrate that by utilizingconventional compositions to form precursor films, anti-fog compositionshaving low anti-fog times, e.g., less than 20 seconds and/or high hazevalues, e.g., greater than 1.5, are undesirably achieved.

While the invention has been described in detail, modifications withinthe spirit and scope of the invention will be readily apparent to thoseof skill in the art. It should be understood that aspects of theinvention and portions of various embodiments and various featuresrecited herein and/or in the appended claims may be combined orinterchanged either in whole or in part. In the foregoing descriptionsof the various embodiments, those embodiments which refer to anotherembodiment may be appropriately combined with other embodiments as willbe appreciated by one of ordinary skill in the art. Furthermore, thoseof ordinary skill in the art will appreciate that the foregoingdescription is by way of example only, and is not intended to limit theinvention.

We claim:
 1. An anti-fog composition, comprising a primary film havingopposing major planar surfaces and a central coplanar region disposedbetween said opposing major planar surfaces, said primary filmcomprising cellulose acetate, plasticizer, and an anti-blocking agenthaving an average particle size ranging from 0.02 microns to 6 microns,wherein the cellulose acetate has a degree of substitution thatincreases from the opposing major planar surfaces toward the centralcoplanar region.
 2. The anti-fog composition of claim 1, wherein theanti-for composition has a degree of substitution at the opposing majorplanar surfaces of about zero.
 3. The anti-fog composition of claim 1,wherein the anti-for composition has a degree of substitution at thecentral coplanar region from 2.0 to 2.6, preferably from 2.2 to 2.55. 4.The anti-fog composition of claim 1, wherein the anti-for compositionhas va fog time greater than 10 seconds and/or a haze value ranging from0.1% to 4.0%, as measured by ASTM D1003.
 5. The anti-fog composition ofclaim 1, wherein the plasticizer is selected from the group consistingof 1,2,3-triacetoxypropane (triacetin), tributyl citrate, triethylcitrate, triphenyl phosphate, tris(clorisopropyl)phosphate, dimethylphthalate, bornan-2-one, PEG-DGE, PPG-DGE, tributyl phosphate, andcombinations thereof.
 6. The anti-fog composition of claim 1, whereinthe plasticizer comprises diethyl phthalate and/or the anti-blockingagent comprises silica.
 7. The anti-fog composition of claim 1, whereinthe primary film comprises from 60 wt % to 95 wt % cellulose acetate,from 5 to 40 wt. % plasticizer and from 0.01 to 10 wt. % anti-blockingagent.
 8. The anti-fog composition of claim 1, wherein the primary filmfurther comprises a releasing agent.
 9. The anti-fog composition ofclaim 1, wherein the anti-fog composition has a thickness ranging from25 microns to 2000 microns.
 10. The anti-fog composition of claim 1,wherein the anti-fog composition does not comprise discrete layers. 11.A consumer product having a planar surface and the anti-fog compositionof claim 1 disposed on said planar surface.
 12. The consumer product ofclaim 11, wherein the consumer product is selected from the groupconsisting of lenses, windows, screens, glass structures, containers,appliances, plastic, refrigerating devices, optical devices, and visors.13. A process for producing an anti-fog composition comprising a primaryfilm, the process comprising the steps of: (a) combining celluloseacetate, a plasticizer, an anti-blocking agent having an averageparticle size ranging from 0.02 microns to 6 microns and solvent to forma dope; (b) casting the dope to form a precursor film; (c) contactingthe precursor film with a caustic solution to form a treated film; (d)washing the treated film to form a washed film; and (e) drying thewashed film to form the primary film.
 14. The process of claim 13,further comprising the step of treating the precursor film with acetoneprior to the contacting step.
 15. The process of claim 13, wherein thecaustic solution comprises an aqueous hydroxide solution.
 16. Theprocess of claim 13, wherein the contacting is conducted for a residencetime ranging from 0.5 minutes to 20 minutes and/or at a temperatureranging from 40° C. to 100° C.
 17. An anti-fog composition, comprising aprimary film having a thickness, opposing major planar surfaces and acentral coplanar region disposed between the opposing major planarsurfaces, the primary film comprising cellulose acetate, plasticizer,and an anti-blocking agent having an average particle size less than 6microns, wherein the degree of substitution throughout the thickness ofthe primary film is substantially uniform.
 18. The anti-fog compositionof claim 17, wherein the degree of substitution of the cellulose acetateat the central coplanar region is not greater than 10% different fromthe degree of substitution of at least one of the opposing major planarsurfaces.
 19. The anti-fog composition of claim 17, wherein the anti-fogcomposition has a fog time greater than 10 seconds and/or a haze valueranging from 0.1% to 4.0%, as measured by ASTM D1003.
 20. The anti-fogcomposition of claim 17, wherein the plasticizer comprises diethylphthalate and/or the anti-blocking agent comprises silica.